CVE-2024-50154

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2024-50154", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-10-21T19:36:19.960Z", "datePublished": "2024-11-07T09:31:30.855Z", "dateUpdated": "2026-08-05T11:42:07.102Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:42:07.102Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().\n\nMartin KaFai Lau reported use-after-free [0] in reqsk_timer_handler().\n\n \"\"\"\n We are seeing a use-after-free from a bpf prog attached to\n trace_tcp_retransmit_synack. The program passes the req->sk to the\n bpf_sk_storage_get_tracing kernel helper which does check for null\n before using it.\n \"\"\"\n\nThe commit 83fccfc3940c (\"inet: fix potential deadlock in\nreqsk_queue_unlink()\") added timer_pending() in reqsk_queue_unlink() not\nto call del_timer_sync() from reqsk_timer_handler(), but it introduced a\nsmall race window.\n\nBefore the timer is called, expire_timers() calls detach_timer(timer, true)\nto clear timer->entry.pprev and marks it as not pending.\n\nIf reqsk_queue_unlink() checks timer_pending() just after expire_timers()\ncalls detach_timer(), TCP will miss del_timer_sync(); the reqsk timer will\ncontinue running and send multiple SYN+ACKs until it expires.\n\nThe reported UAF could happen if req->sk is close()d earlier than the timer\nexpiration, which is 63s by default.\n\nThe scenario would be\n\n 1. inet_csk_complete_hashdance() calls inet_csk_reqsk_queue_drop(),\n but del_timer_sync() is missed\n\n 2. reqsk timer is executed and scheduled again\n\n 3. req->sk is accept()ed and reqsk_put() decrements rsk_refcnt, but\n reqsk timer still has another one, and inet_csk_accept() does not\n clear req->sk for non-TFO sockets\n\n 4. sk is close()d\n\n 5. reqsk timer is executed again, and BPF touches req->sk\n\nLet's not use timer_pending() by passing the caller context to\n__inet_csk_reqsk_queue_drop().\n\nNote that reqsk timer is pinned, so the issue does not happen in most\nuse cases. [1]\n\n[0]\nBUG: KFENCE: use-after-free read in bpf_sk_storage_get_tracing+0x2e/0x1b0\n\nUse-after-free read at 0x00000000a891fb3a (in kfence-#1):\nbpf_sk_storage_get_tracing+0x2e/0x1b0\nbpf_prog_5ea3e95db6da0438_tcp_retransmit_synack+0x1d20/0x1dda\nbpf_trace_run2+0x4c/0xc0\ntcp_rtx_synack+0xf9/0x100\nreqsk_timer_handler+0xda/0x3d0\nrun_timer_softirq+0x292/0x8a0\nirq_exit_rcu+0xf5/0x320\nsysvec_apic_timer_interrupt+0x6d/0x80\nasm_sysvec_apic_timer_interrupt+0x16/0x20\nintel_idle_irq+0x5a/0xa0\ncpuidle_enter_state+0x94/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb\n\nkfence-#1: 0x00000000a72cc7b6-0x00000000d97616d9, size=2376, cache=TCPv6\n\nallocated by task 0 on cpu 9 at 260507.901592s:\nsk_prot_alloc+0x35/0x140\nsk_clone_lock+0x1f/0x3f0\ninet_csk_clone_lock+0x15/0x160\ntcp_create_openreq_child+0x1f/0x410\ntcp_v6_syn_recv_sock+0x1da/0x700\ntcp_check_req+0x1fb/0x510\ntcp_v6_rcv+0x98b/0x1420\nipv6_list_rcv+0x2258/0x26e0\nnapi_complete_done+0x5b1/0x2990\nmlx5e_napi_poll+0x2ae/0x8d0\nnet_rx_action+0x13e/0x590\nirq_exit_rcu+0xf5/0x320\ncommon_interrupt+0x80/0x90\nasm_common_interrupt+0x22/0x40\ncpuidle_enter_state+0xfb/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb\n\nfreed by task 0 on cpu 9 at 260507.927527s:\nrcu_core_si+0x4ff/0xf10\nirq_exit_rcu+0xf5/0x320\nsysvec_apic_timer_interrupt+0x6d/0x80\nasm_sysvec_apic_timer_interrupt+0x16/0x20\ncpuidle_enter_state+0xfb/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb"}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - The vulnerability lives in the TCP/DCCP connection-request path and is driven entirely by packets from a remote peer \u2014 a SYN arms the pinned reqsk timer, and a final ACK, RST, or crafted ICMP/ICMPv6 error races `inet_csk_reqsk_queue_drop()` against it. Any internet-facing listening TCP socket is reachable with no local access.\nAC:L - The attacker controls both sides of the race: it chooses when the timer is armed (SYN \u2192 `jiffies + TCP_TIMEOUT_INIT`, 1 s) and when the drop executes (ACK/RST/ICMP at t\u22481 s), and can run thousands of connections in parallel to hit the window reliably. The `TIMER_PINNED` same-CPU argument is defeated by attacker-chosen droppers that run on a different CPU \u2014 ICMP errors via `tcp_req_err()`, plus `tcp_abort()` and `inet_twsk_purge()` in process/workqueue context.\nPR:N - The entire path is pre-authentication TCP three-way-handshake and ICMP error handling in the kernel network stack, executed before any application-level credential check. An unauthenticated remote host merely needs to connect to a listening port.\nUI:N - No victim action is required; the server's ordinary `accept()`/`close()` lifecycle completes the scenario, and the ICMP and RST droppers need no local activity at all.\nS:U - The corruption is confined to kernel memory within the same security authority \u2014 freed socket objects and listener accept-queue accounting. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - This is a use-after-free read of a freed 2376-byte `struct tcp_sock` (KFENCE-confirmed); `bpf_sk_storage_get()` reads `sk->sk_state` and follows the stale `sk->sk_bpf_storage` pointer, returning `sdata->data` to the caller. An attacker who grooms the reallocated slab object turns that into an arbitrary kernel read primitive.\nI:H - The same UAF yields a write primitive \u2014 with `BPF_SK_STORAGE_GET_F_CREATE` the helper performs `refcount_inc_not_zero(&sk->sk_refcnt)` and `bpf_local_storage_update()` against the freed/reallocated object, and per CVSS kernel guidance a use-after-free is treated as exploitable for control-flow hijacking. Independently, the double `atomic_dec(&queue->young)` persistently corrupts the listener's SYN-queue accounting.\nA:H - Dereferencing the freed socket oopses or panics the kernel, and the condition is remotely repeatable across many connections. Even without a crash, each hijacked request floods SYN+ACK retransmissions for ~63 s and the underflowed `young` counter permanently clamps `max_syn_ack_retries` to 2, degrading the listener for its remaining lifetime."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/ipv4/inet_connection_sock.c"], "versions": [{"version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "106e457953315e476b3642ef24be25ed862aaba3", "status": "affected", "versionType": "git"}, {"version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "c964bf65f80a14288d767023a1b300b30f5b9cd0", "status": "affected", "versionType": "git"}, {"version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "8459d61fbf24967839a70235165673148c7c7f17", "status": "affected", "versionType": "git"}, {"version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "5071beb59ee416e8ab456ac8647a4dabcda823b1", "status": "affected", "versionType": "git"}, {"version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "997ae8da14f1639ce6fb66a063dab54031cd61b3", "status": "affected", "versionType": "git"}, {"version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "51e34db64f4e43c7b055ccf881b7f3e0c31bb26d", "status": "affected", "versionType": "git"}, {"version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "e8c526f2bdf1845bedaf6a478816a3d06fa78b8f", "status": "affected", "versionType": "git"}, {"version": "d3a1196bfc462943694623412d8e03aaf172bdc1", "status": "affected", "versionType": "git"}, {"version": "4.1.11", "lessThan": "4.2", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/ipv4/inet_connection_sock.c"], "versions": [{"version": "4.2", "status": "affected"}, {"version": "0", "lessThan": "4.2", "status": "unaffected", "versionType": "semver"}, {"version": "5.4.293", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.237", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.170", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.115", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.59", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.11.6", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "5.4.293"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "5.10.237"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "5.15.170"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.1.115"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.6.59"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.11.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.12"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.1.11"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/106e457953315e476b3642ef24be25ed862aaba3"}, {"url": "https://git.kernel.org/stable/c/c964bf65f80a14288d767023a1b300b30f5b9cd0"}, {"url": "https://git.kernel.org/stable/c/8459d61fbf24967839a70235165673148c7c7f17"}, {"url": "https://git.kernel.org/stable/c/5071beb59ee416e8ab456ac8647a4dabcda823b1"}, {"url": "https://git.kernel.org/stable/c/997ae8da14f1639ce6fb66a063dab54031cd61b3"}, {"url": "https://git.kernel.org/stable/c/51e34db64f4e43c7b055ccf881b7f3e0c31bb26d"}, {"url": "https://git.kernel.org/stable/c/e8c526f2bdf1845bedaf6a478816a3d06fa78b8f"}], "title": "tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}}, {"other": {"type": "ssvc", "content": {"id": "CVE-2024-50154", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2024-12-11T14:25:48.087506Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free"}]}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-12-11T14:58:32.999Z"}}, {"title": "CVE Program Container", "references": [{"url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"}, {"url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"}], 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{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CVE Program Container", "references": [{"url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"}, {"url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T22:26:13.271Z"}}, {"title": "CISA ADP Vulnrichment", "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}}, {"other": {"type": "ssvc", "content": {"id": "CVE-2024-50154", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2024-12-11T14:25:48.087506Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free"}]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-12-11T14:25:49.409Z"}}], "cna": {"title": "tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().", "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "106e457953315e476b3642ef24be25ed862aaba3", "versionType": "git"}, {"status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "c964bf65f80a14288d767023a1b300b30f5b9cd0", "versionType": "git"}, {"status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "8459d61fbf24967839a70235165673148c7c7f17", "versionType": "git"}, {"status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "5071beb59ee416e8ab456ac8647a4dabcda823b1", "versionType": "git"}, {"status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "997ae8da14f1639ce6fb66a063dab54031cd61b3", "versionType": "git"}, {"status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "51e34db64f4e43c7b055ccf881b7f3e0c31bb26d", "versionType": "git"}, {"status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "e8c526f2bdf1845bedaf6a478816a3d06fa78b8f", "versionType": "git"}, {"status": "affected", "version": "d3a1196bfc462943694623412d8e03aaf172bdc1", "versionType": "git"}, {"status": "affected", "version": "4.1.11", "lessThan": "4.2", "versionType": "semver"}], "programFiles": ["net/ipv4/inet_connection_sock.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "4.2"}, {"status": "unaffected", "version": "0", "lessThan": "4.2", "versionType": "semver"}, {"status": "unaffected", "version": "5.4.293", "versionType": "semver", "lessThanOrEqual": "5.4.*"}, {"status": "unaffected", "version": "5.10.237", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.170", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.115", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.59", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.11.6", "versionType": "semver", "lessThanOrEqual": "6.11.*"}, {"status": "unaffected", "version": "6.12", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["net/ipv4/inet_connection_sock.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/106e457953315e476b3642ef24be25ed862aaba3"}, {"url": "https://git.kernel.org/stable/c/c964bf65f80a14288d767023a1b300b30f5b9cd0"}, {"url": "https://git.kernel.org/stable/c/8459d61fbf24967839a70235165673148c7c7f17"}, {"url": "https://git.kernel.org/stable/c/5071beb59ee416e8ab456ac8647a4dabcda823b1"}, {"url": "https://git.kernel.org/stable/c/997ae8da14f1639ce6fb66a063dab54031cd61b3"}, {"url": "https://git.kernel.org/stable/c/51e34db64f4e43c7b055ccf881b7f3e0c31bb26d"}, {"url": "https://git.kernel.org/stable/c/e8c526f2bdf1845bedaf6a478816a3d06fa78b8f"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().\n\nMartin KaFai Lau reported use-after-free [0] in reqsk_timer_handler().\n\n \"\"\"\n We are seeing a use-after-free from a bpf prog attached to\n trace_tcp_retransmit_synack. The program passes the req->sk to the\n bpf_sk_storage_get_tracing kernel helper which does check for null\n before using it.\n \"\"\"\n\nThe commit 83fccfc3940c (\"inet: fix potential deadlock in\nreqsk_queue_unlink()\") added timer_pending() in reqsk_queue_unlink() not\nto call del_timer_sync() from reqsk_timer_handler(), but it introduced a\nsmall race window.\n\nBefore the timer is called, expire_timers() calls detach_timer(timer, true)\nto clear timer->entry.pprev and marks it as not pending.\n\nIf reqsk_queue_unlink() checks timer_pending() just after expire_timers()\ncalls detach_timer(), TCP will miss del_timer_sync(); the reqsk timer will\ncontinue running and send multiple SYN+ACKs until it expires.\n\nThe reported UAF could happen if req->sk is close()d earlier than the timer\nexpiration, which is 63s by default.\n\nThe scenario would be\n\n 1. inet_csk_complete_hashdance() calls inet_csk_reqsk_queue_drop(),\n but del_timer_sync() is missed\n\n 2. reqsk timer is executed and scheduled again\n\n 3. req->sk is accept()ed and reqsk_put() decrements rsk_refcnt, but\n reqsk timer still has another one, and inet_csk_accept() does not\n clear req->sk for non-TFO sockets\n\n 4. sk is close()d\n\n 5. reqsk timer is executed again, and BPF touches req->sk\n\nLet's not use timer_pending() by passing the caller context to\n__inet_csk_reqsk_queue_drop().\n\nNote that reqsk timer is pinned, so the issue does not happen in most\nuse cases. [1]\n\n[0]\nBUG: KFENCE: use-after-free read in bpf_sk_storage_get_tracing+0x2e/0x1b0\n\nUse-after-free read at 0x00000000a891fb3a (in kfence-#1):\nbpf_sk_storage_get_tracing+0x2e/0x1b0\nbpf_prog_5ea3e95db6da0438_tcp_retransmit_synack+0x1d20/0x1dda\nbpf_trace_run2+0x4c/0xc0\ntcp_rtx_synack+0xf9/0x100\nreqsk_timer_handler+0xda/0x3d0\nrun_timer_softirq+0x292/0x8a0\nirq_exit_rcu+0xf5/0x320\nsysvec_apic_timer_interrupt+0x6d/0x80\nasm_sysvec_apic_timer_interrupt+0x16/0x20\nintel_idle_irq+0x5a/0xa0\ncpuidle_enter_state+0x94/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb\n\nkfence-#1: 0x00000000a72cc7b6-0x00000000d97616d9, size=2376, cache=TCPv6\n\nallocated by task 0 on cpu 9 at 260507.901592s:\nsk_prot_alloc+0x35/0x140\nsk_clone_lock+0x1f/0x3f0\ninet_csk_clone_lock+0x15/0x160\ntcp_create_openreq_child+0x1f/0x410\ntcp_v6_syn_recv_sock+0x1da/0x700\ntcp_check_req+0x1fb/0x510\ntcp_v6_rcv+0x98b/0x1420\nipv6_list_rcv+0x2258/0x26e0\nnapi_complete_done+0x5b1/0x2990\nmlx5e_napi_poll+0x2ae/0x8d0\nnet_rx_action+0x13e/0x590\nirq_exit_rcu+0xf5/0x320\ncommon_interrupt+0x80/0x90\nasm_common_interrupt+0x22/0x40\ncpuidle_enter_state+0xfb/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb\n\nfreed by task 0 on cpu 9 at 260507.927527s:\nrcu_core_si+0x4ff/0xf10\nirq_exit_rcu+0xf5/0x320\nsysvec_apic_timer_interrupt+0x6d/0x80\nasm_sysvec_apic_timer_interrupt+0x16/0x20\ncpuidle_enter_state+0xfb/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb"}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.4.293", "versionStartIncluding": "4.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.237", "versionStartIncluding": "4.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.170", "versionStartIncluding": "4.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.115", "versionStartIncluding": "4.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.59", "versionStartIncluding": "4.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.11.6", "versionStartIncluding": "4.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12", "versionStartIncluding": "4.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "4.1.11"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-23T15:54:38.529Z"}}}, "cveMetadata": {"cveId": "CVE-2024-50154", "state": "PUBLISHED", "dateUpdated": "2026-05-23T15:54:38.529Z", "dateReserved": "2024-10-21T19:36:19.960Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2024-11-07T09:31:30.855Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/ipv4/inet_connection_sock.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "106e457953315e476b3642ef24be25ed862aaba3", "status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "versionType": "git"}, {"lessThan": "c964bf65f80a14288d767023a1b300b30f5b9cd0", "status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "versionType": "git"}, {"lessThan": "8459d61fbf24967839a70235165673148c7c7f17", "status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "versionType": "git"}, {"lessThan": "5071beb59ee416e8ab456ac8647a4dabcda823b1", "status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "versionType": "git"}, {"lessThan": "997ae8da14f1639ce6fb66a063dab54031cd61b3", "status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "versionType": "git"}, {"lessThan": "51e34db64f4e43c7b055ccf881b7f3e0c31bb26d", "status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "versionType": "git"}, {"lessThan": "e8c526f2bdf1845bedaf6a478816a3d06fa78b8f", "status": "affected", "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "versionType": "git"}, {"status": "affected", "version": "d3a1196bfc462943694623412d8e03aaf172bdc1", "versionType": "git"}, {"lessThan": "4.2", "status": "affected", "version": "4.1.11", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/ipv4/inet_connection_sock.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.2"}, {"lessThan": "4.2", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.4.*", "status": "unaffected", "version": "5.4.293", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.237", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.170", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.115", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.59", "versionType": "semver"}, {"lessThanOrEqual": "6.11.*", "status": "unaffected", "version": "6.11.6", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.12", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "3CD6E092-00BA-470A-BD6E-9FF38E84DB99", "versionEndExcluding": "4.2", "versionStartIncluding": "4.1.11", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "D37DEB92-5329-47EC-94B1-051761C1F534", "versionEndExcluding": "5.15.170", "versionStartIncluding": "4.2", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "C08A77A6-E42E-4EFD-B5A1-2BF6CBBB42AE", "versionEndExcluding": "6.1.115", "versionStartIncluding": "5.16", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "5D15CA59-D15C-4ACD-8B03-A072DEAD2081", "versionEndExcluding": "6.6.59", "versionStartIncluding": "6.2", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "E4486B12-007B-4794-9857-F07145637AA1", "versionEndExcluding": "6.11.6", "versionStartIncluding": "6.7", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:*", "matchCriteriaId": "7F361E1D-580F-4A2D-A509-7615F73167A1", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:*", "matchCriteriaId": "925478D0-3E3D-4E6F-ACD5-09F28D5DF82C", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:*", "matchCriteriaId": "3C95E234-D335-4B6C-96BF-E2CEBD8654ED", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().\n\nMartin KaFai Lau reported use-after-free [0] in reqsk_timer_handler().\n\n \"\"\"\n We are seeing a use-after-free from a bpf prog attached to\n trace_tcp_retransmit_synack. The program passes the req->sk to the\n bpf_sk_storage_get_tracing kernel helper which does check for null\n before using it.\n \"\"\"\n\nThe commit 83fccfc3940c (\"inet: fix potential deadlock in\nreqsk_queue_unlink()\") added timer_pending() in reqsk_queue_unlink() not\nto call del_timer_sync() from reqsk_timer_handler(), but it introduced a\nsmall race window.\n\nBefore the timer is called, expire_timers() calls detach_timer(timer, true)\nto clear timer->entry.pprev and marks it as not pending.\n\nIf reqsk_queue_unlink() checks timer_pending() just after expire_timers()\ncalls detach_timer(), TCP will miss del_timer_sync(); the reqsk timer will\ncontinue running and send multiple SYN+ACKs until it expires.\n\nThe reported UAF could happen if req->sk is close()d earlier than the timer\nexpiration, which is 63s by default.\n\nThe scenario would be\n\n 1. inet_csk_complete_hashdance() calls inet_csk_reqsk_queue_drop(),\n but del_timer_sync() is missed\n\n 2. reqsk timer is executed and scheduled again\n\n 3. req->sk is accept()ed and reqsk_put() decrements rsk_refcnt, but\n reqsk timer still has another one, and inet_csk_accept() does not\n clear req->sk for non-TFO sockets\n\n 4. sk is close()d\n\n 5. reqsk timer is executed again, and BPF touches req->sk\n\nLet's not use timer_pending() by passing the caller context to\n__inet_csk_reqsk_queue_drop().\n\nNote that reqsk timer is pinned, so the issue does not happen in most\nuse cases. [1]\n\n[0]\nBUG: KFENCE: use-after-free read in bpf_sk_storage_get_tracing+0x2e/0x1b0\n\nUse-after-free read at 0x00000000a891fb3a (in kfence-#1):\nbpf_sk_storage_get_tracing+0x2e/0x1b0\nbpf_prog_5ea3e95db6da0438_tcp_retransmit_synack+0x1d20/0x1dda\nbpf_trace_run2+0x4c/0xc0\ntcp_rtx_synack+0xf9/0x100\nreqsk_timer_handler+0xda/0x3d0\nrun_timer_softirq+0x292/0x8a0\nirq_exit_rcu+0xf5/0x320\nsysvec_apic_timer_interrupt+0x6d/0x80\nasm_sysvec_apic_timer_interrupt+0x16/0x20\nintel_idle_irq+0x5a/0xa0\ncpuidle_enter_state+0x94/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb\n\nkfence-#1: 0x00000000a72cc7b6-0x00000000d97616d9, size=2376, cache=TCPv6\n\nallocated by task 0 on cpu 9 at 260507.901592s:\nsk_prot_alloc+0x35/0x140\nsk_clone_lock+0x1f/0x3f0\ninet_csk_clone_lock+0x15/0x160\ntcp_create_openreq_child+0x1f/0x410\ntcp_v6_syn_recv_sock+0x1da/0x700\ntcp_check_req+0x1fb/0x510\ntcp_v6_rcv+0x98b/0x1420\nipv6_list_rcv+0x2258/0x26e0\nnapi_complete_done+0x5b1/0x2990\nmlx5e_napi_poll+0x2ae/0x8d0\nnet_rx_action+0x13e/0x590\nirq_exit_rcu+0xf5/0x320\ncommon_interrupt+0x80/0x90\nasm_common_interrupt+0x22/0x40\ncpuidle_enter_state+0xfb/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb\n\nfreed by task 0 on cpu 9 at 260507.927527s:\nrcu_core_si+0x4ff/0xf10\nirq_exit_rcu+0xf5/0x320\nsysvec_apic_timer_interrupt+0x6d/0x80\nasm_sysvec_apic_timer_interrupt+0x16/0x20\ncpuidle_enter_state+0xfb/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb"}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: tcp/dccp: No use timer_pending() en reqsk_queue_unlink(). Martin KaFai Lau inform\u00f3 de un use-after-free [0] en reqsk_timer_handler(). \"\"\" Estamos viendo un use-after-free de un programa bpf adjunto a trace_tcp_retransmit_synack. El programa pasa el req->sk al ayudante del kernel bpf_sk_storage_get_tracing que comprueba si hay valores nulos antes de usarlo. \"\"\" El commit 83fccfc3940c (\"inet: soluciona un posible bloqueo en reqsk_queue_unlink()\") agreg\u00f3 timer_pending() en reqsk_queue_unlink() para no llamar a del_timer_sync() desde reqsk_timer_handler(), pero introdujo una peque\u00f1a ventana de ejecuci\u00f3n. Antes de que se llame al temporizador, expire_timers() llama a detach_timer(timer, true) para borrar timer->entry.pprev y lo marca como no pendiente. Si reqsk_queue_unlink() comprueba timer_pending() justo despu\u00e9s de que expire_timers() llame a detach_timer(), TCP no detectar\u00e1 del_timer_sync(); el temporizador reqsk seguir\u00e1 funcionando y enviar\u00e1 varios SYN+ACK hasta que expire. El UAF informado podr\u00eda ocurrir si se cierra req->sk antes de la expiraci\u00f3n del temporizador, que es 63 s por defecto. El escenario ser\u00eda 1. inet_csk_complete_hashdance() llama a inet_csk_reqsk_queue_drop(), pero se omite del_timer_sync() 2. se ejecuta el temporizador reqsk y se programa nuevamente 3. se acepta req->sk y reqsk_put() decrementa rsk_refcnt, pero el temporizador reqsk a\u00fan tiene otro, e inet_csk_accept() no borra req->sk para sockets que no sean TFO 4. se cierra sk 5. se ejecuta nuevamente el temporizador reqsk y BPF toca req->sk No usemos timer_pending() pasando el contexto del llamador a __inet_csk_reqsk_queue_drop(). Tenga en cuenta que el temporizador reqsk est\u00e1 fijado, por lo que el problema no ocurre en la mayor\u00eda de los casos de uso. [1] [0] ERROR: KFENCE: lectura de use-after-free en bpf_sk_storage_get_tracing+0x2e/0x1b0 Lectura de use-after-free en 0x00000000a891fb3a (en kfence-#1): bpf_sk_storage_get_tracing+0x2e/0x1b0 bpf_prog_5ea3e95db6da0438_tcp_retransmit_synack+0x1d20/0x1dda bpf_trace_run2+0x4c/0xc0 tcp_rtx_synack+0xf9/0x100 reqsk_timer_handler+0xda/0x3d0 run_timer_softirq+0x292/0x8a0 irq_exit_rcu+0xf5/0x320 sysvec_apic_timer_interrupt+0x6d/0x80 asm_sysvec_apic_timer_interrupt+0x16/0x20 intel_idle_irq+0x5a/0xa0 cpuidle_enter_state+0x94/0x273 cpu_startup_entry+0x15e/0x260 start_secondary+0x8a/0x90 secondary_startup_64_no_verify+0xfa/0xfb kfence-#1: 0x00000000a72cc7b6-0x00000000d97616d9, tama\u00f1o=2376, cach\u00e9=TCPv6 asignado por la tarea 0 en la CPU 9 en 260507.901592s: sk_prot_alloc+0x35/0x140 sk_clone_lock+0x1f/0x3f0 inet_csk_clone_lock+0x15/0x160 tcp_create_openreq_child+0x1f/0x410 tcp_v6_syn_recv_sock+0x1da/0x700 tcp_check_req+0x1fb/0x510 tcp_v6_rcv+0x98b/0x1420 ipv6_list_rcv+0x2258/0x26e0 napi_complete_done+0x5b1/0x2990 mlx5e_napi_poll+0x2ae/0x8d0 net_rx_action+0x13e/0x590 irq_exit_rcu+0xf5/0x320 common_interrupt+0x80/0x90 asm_common_interrupt+0x22/0x40 cpuidle_enter_state+0xfb/0x273 cpu_startup_entry+0x15e/0x260 start_secondary+0x8a/0x90 secondary_startup_64_no_verify+0xfa/0xfb liberado por la tarea 0 en la CPU 9 a las 260507.927527 s: rcu_core_si+0x4ff/0xf10 irq_exit_rcu+0xf5/0x320 sysvec_apic_timer_interrupt+0x6d/0x80 asm_sysvec_apic_timer_interrupt+0x16/0x20 cpu_idle_entrada_estado+0xfb/0x273 cpu_inicio_entrada+0x15e/0x260 inicio_secundario+0x8a/0x90 inicio_secundario_64_sin_verificaci\u00f3n+0xfa/0xfb"}], "id": "CVE-2024-50154", "lastModified": "2026-08-04T11:21:26.317", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"cvssData": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.0, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.0, "impactScore": 5.9, "source": "nvd@nist.gov", "type": "Primary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2024-50154", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2024-12-11T14:25:48.087506Z", "version": "2.0.3"}}]}, "published": "2024-11-07T10:15:06.987", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/106e457953315e476b3642ef24be25ed862aaba3"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/5071beb59ee416e8ab456ac8647a4dabcda823b1"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/51e34db64f4e43c7b055ccf881b7f3e0c31bb26d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/8459d61fbf24967839a70235165673148c7c7f17"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/997ae8da14f1639ce6fb66a063dab54031cd61b3"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c964bf65f80a14288d767023a1b300b30f5b9cd0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/e8c526f2bdf1845bedaf6a478816a3d06fa78b8f"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "nvd@nist.gov", "type": "Primary"}, {"description": [{"lang": "en", "value": "CWE-416"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{"affected_release": [{"advisory": "RHSA-2025:0578", "cpe": "cpe:/a:redhat:enterprise_linux:9", "package": "kernel-0:5.14.0-503.22.1.el9_5", "product_name": "Red Hat Enterprise Linux 9", "release_date": "2025-01-22T00:00:00Z"}, {"advisory": "RHSA-2025:0578", "cpe": "cpe:/o:redhat:enterprise_linux:9", "package": "kernel-0:5.14.0-503.22.1.el9_5", "product_name": "Red Hat Enterprise Linux 9", "release_date": "2025-01-22T00:00:00Z"}], "bugzilla": {"description": "kernel: tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().", "id": "2324313", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2324313"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "verified"}, "cwe": "CWE-416", "details": ["In the Linux kernel, the following vulnerability has been resolved:\ntcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().\nMartin KaFai Lau reported use-after-free [0] in reqsk_timer_handler().\n\"\"\"\nWe are seeing a use-after-free from a bpf prog attached to\ntrace_tcp_retransmit_synack. The program passes the req->sk to the\nbpf_sk_storage_get_tracing kernel helper which does check for null\nbefore using it.\n\"\"\"\nThe commit 83fccfc3940c (\"inet: fix potential deadlock in\nreqsk_queue_unlink()\") added timer_pending() in reqsk_queue_unlink() not\nto call del_timer_sync() from reqsk_timer_handler(), but it introduced a\nsmall race window.\nBefore the timer is called, expire_timers() calls detach_timer(timer, true)\nto clear timer->entry.pprev and marks it as not pending.\nIf reqsk_queue_unlink() checks timer_pending() just after expire_timers()\ncalls detach_timer(), TCP will miss del_timer_sync(); the reqsk timer will\ncontinue running and send multiple SYN+ACKs until it expires.\nThe reported UAF could happen if req->sk is close()d earlier than the timer\nexpiration, which is 63s by default.\nThe scenario would be\n1. inet_csk_complete_hashdance() calls inet_csk_reqsk_queue_drop(),\nbut del_timer_sync() is missed\n2. reqsk timer is executed and scheduled again\n3. req->sk is accept()ed and reqsk_put() decrements rsk_refcnt, but\nreqsk timer still has another one, and inet_csk_accept() does not\nclear req->sk for non-TFO sockets\n4. sk is close()d\n5. reqsk timer is executed again, and BPF touches req->sk\nLet's not use timer_pending() by passing the caller context to\n__inet_csk_reqsk_queue_drop().\nNote that reqsk timer is pinned, so the issue does not happen in most\nuse cases. [1]\n[0]\nBUG: KFENCE: use-after-free read in bpf_sk_storage_get_tracing+0x2e/0x1b0\nUse-after-free read at 0x00000000a891fb3a (in kfence-#1):\nbpf_sk_storage_get_tracing+0x2e/0x1b0\nbpf_prog_5ea3e95db6da0438_tcp_retransmit_synack+0x1d20/0x1dda\nbpf_trace_run2+0x4c/0xc0\ntcp_rtx_synack+0xf9/0x100\nreqsk_timer_handler+0xda/0x3d0\nrun_timer_softirq+0x292/0x8a0\nirq_exit_rcu+0xf5/0x320\nsysvec_apic_timer_interrupt+0x6d/0x80\nasm_sysvec_apic_timer_interrupt+0x16/0x20\nintel_idle_irq+0x5a/0xa0\ncpuidle_enter_state+0x94/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb\nkfence-#1: 0x00000000a72cc7b6-0x00000000d97616d9, size=2376, cache=TCPv6\nallocated by task 0 on cpu 9 at 260507.901592s:\nsk_prot_alloc+0x35/0x140\nsk_clone_lock+0x1f/0x3f0\ninet_csk_clone_lock+0x15/0x160\ntcp_create_openreq_child+0x1f/0x410\ntcp_v6_syn_recv_sock+0x1da/0x700\ntcp_check_req+0x1fb/0x510\ntcp_v6_rcv+0x98b/0x1420\nipv6_list_rcv+0x2258/0x26e0\nnapi_complete_done+0x5b1/0x2990\nmlx5e_napi_poll+0x2ae/0x8d0\nnet_rx_action+0x13e/0x590\nirq_exit_rcu+0xf5/0x320\ncommon_interrupt+0x80/0x90\nasm_common_interrupt+0x22/0x40\ncpuidle_enter_state+0xfb/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb\nfreed by task 0 on cpu 9 at 260507.927527s:\nrcu_core_si+0x4ff/0xf10\nirq_exit_rcu+0xf5/0x320\nsysvec_apic_timer_interrupt+0x6d/0x80\nasm_sysvec_apic_timer_interrupt+0x16/0x20\ncpuidle_enter_state+0xfb/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb", "A use-after-free (UAF) vulnerability was found and fixed in the Linux kernel's TCP subsystem related to request socket (reqsk) timers during handshake handling. This issue stems from a race condition caused by relying on `timer_pending()` in `reqsk_queue_unlink()`. This could result in the timer continuing to run after the socket (`req->sk`) is freed, allowing BPF programs to access invalid memory."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."}, "name": "CVE-2024-50154", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Will not fix", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2024-11-07T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2024-50154\nhttps://nvd.nist.gov/vuln/detail/CVE-2024-50154\nhttps://lore.kernel.org/linux-cve-announce/2024110745-CVE-2024-50154-0259@gregkh/T"], "statement": "This vulnerability is classified as moderate severity rather than important because the issue primarily affects a narrow set of conditions, notably when BPF programs are involved in tracing TCP retransmissions. In most scenarios, the reqsk timer is pinned and the race condition is unlikely to be triggered. Additionally, the problem only occurs if the request socket (`req->sk`) is closed while the timer is still pending, which is an uncommon sequence of events. While the potential for a use-after-free (UAF) exists, it requires specific timing and conditions to exploit, limiting its overall risk and impact on typical systems.", "threat_severity": "Moderate"}

{}