CVE-2026-64541

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-64541", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.795Z", "datePublished": "2026-07-27T20:10:34.439Z", "dateUpdated": "2026-10-19T20:48:39.587Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:57:17.774Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket\n\nsmc_cdc_rx_handler() looks up the connection by token under the link\ngroup's conns_lock, drops the lock, and then dereferences conn and the\nsmc_sock derived from it, ending in sock_hold(&smc->sk) inside\nsmc_cdc_msg_recv(). No reference is held across the lock release.\n\nThe only reference pinning the socket while the connection is\ndiscoverable in the link group is taken in smc_lgr_register_conn()\n(sock_hold) and dropped in __smc_lgr_unregister_conn() (sock_put), both\nunder conns_lock. Once the handler drops conns_lock, a concurrent\nclose() -> smc_release() -> smc_conn_free() -> smc_lgr_unregister_conn()\ncan drop that reference and free the smc_sock, so the handler's later\nsock_hold() runs on freed memory:\n\n WARNING: lib/refcount.c:25 at refcount_warn_saturate\n Workqueue: rxe_wq do_work\n refcount_warn_saturate (lib/refcount.c:25)\n smc_cdc_msg_recv (net/smc/smc_cdc.c:430)\n smc_cdc_rx_handler (net/smc/smc_cdc.c:502)\n smc_wr_rx_tasklet_fn (net/smc/smc_wr.c:445)\n tasklet_action_common (kernel/softirq.c:938)\n handle_softirqs (kernel/softirq.c:622)\n Kernel panic - not syncing: panic_on_warn set\n\nOnly SMC-R is affected. The SMC-D receive tasklet is stopped by\ntasklet_kill(&conn->rx_tsklet) in smc_conn_free() before the connection\nis unregistered, so it cannot run concurrently with the free.\n\nTake the socket reference while still holding conns_lock, so the\nregistration reference can no longer be the last one, and drop it once\nthe handler is done."}], "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 vulnerable handler is driven entirely by a CDC control message sent by the remote SMC-R peer over the RDMA link, with an attacker-chosen `token` field and no local syscall involvement. SMC-R runs over RoCEv2 (IP/UDP-routable, port 4791) with the CLC handshake over plain TCP, and SMC-Rv2 explicitly supports non-local/routed peers, so the attacker need not share an L2 segment.\nAC:L - The attacker controls both sides of the race: it chooses when to emit CDC messages and which connection to target (the alert token is disclosed to it in the CLC accept/confirm), and it can drive the teardown side itself via CDC close/abort flags into `smc_close_passive_work()` or a stale seqno with `failover_validation` into `abort_work` -> `smc_conn_kill()`. The race can be retried indefinitely across many connections in the same link group, and was reproduced in practice with soft-RoCE.\nPR:N - Establishing an SMC-R connection to a listening SMC socket requires no credentials \u2014 SMC has no authentication layer of its own, exactly like plain TCP. Everything after connection establishment (sending CDC messages with a chosen token, signalling close/abort) is available to an unauthenticated peer.\nUI:N - The CDC message is processed in a softirq tasklet from the RDMA completion queue with no involvement from any local user or application action. No victim interaction of any kind is needed.\nS:U - The corruption is confined to kernel memory within the same security authority; there is no VM, IOMMU, or sandbox boundary crossed. This is a standard in-kernel use-after-free.\nC:H - The freed `smc_sock` is reused type-safely as another live socket, so attacker-supplied cursors applied by `smc_cdc_msg_recv_action()` break the `0 <= bytes_to_rcv <= rmb_desc->len` invariant and make `smc_rx_recvmsg()` hand stale RMB contents to userspace, while the urgent-data path reads `*(base + conn->urg_curs.count - 1)` at an attacker-chosen offset. Once the slab page is reclaimed after the RCU grace period, reuse is unconstrained, giving a general kernel-memory read primitive.\nI:H - `sock_hold()` on an already-zero refcount followed by `sock_put()` re-enters `sk_free()`, yielding a double free, and the handler additionally writes `sk_err`/`sk_shutdown`, makes indirect calls through `sk_data_ready()`/`sk_write_space()`, and `queue_work()`s a freed `work_struct`. These are classic heap-spray and control-flow-hijack primitives leading to arbitrary kernel write.\nA:H - The reported symptom is `refcount_warn_saturate` from `smc_cdc_msg_recv()`, which is an immediate kernel panic on `panic_on_warn` systems, and dereferencing freed memory in softirq context otherwise oopses. The attacker can trigger it repeatedly without authentication."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/smc/smc_cdc.c"], "versions": [{"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "8de4f665d0febfb92803dece377791a563fc7041", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "8145b432136285e01091815b48ceb2dae261f262", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "1951bffbc6493ec34cff3956b29d4bc6606904a6", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "647b19e5cc145a2f1f685ae8ff3805a17356888c", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "472e9d7c0d5b03be3ff91ff941f57da822b031bc", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "3bfb96d9bc6a7ed0b99c7db329cc2e22a28d84bb", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "ce5aa8084329351086894aa34d77e40301d5bd3d", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "9d160b35cc34a2ba8229d07651468a7848325135", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/smc/smc_cdc.c"], "versions": [{"version": "4.18", "status": "affected"}, {"version": "0", "lessThan": "4.18", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "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": "4.18", "versionEndExcluding": "5.10.261"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "5.15.212"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.1.178"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.6.145"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.12.97"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.18.40"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/8de4f665d0febfb92803dece377791a563fc7041"}, {"url": "https://git.kernel.org/stable/c/8145b432136285e01091815b48ceb2dae261f262"}, {"url": "https://git.kernel.org/stable/c/1951bffbc6493ec34cff3956b29d4bc6606904a6"}, {"url": "https://git.kernel.org/stable/c/647b19e5cc145a2f1f685ae8ff3805a17356888c"}, {"url": "https://git.kernel.org/stable/c/472e9d7c0d5b03be3ff91ff941f57da822b031bc"}, {"url": "https://git.kernel.org/stable/c/3bfb96d9bc6a7ed0b99c7db329cc2e22a28d84bb"}, {"url": "https://git.kernel.org/stable/c/ce5aa8084329351086894aa34d77e40301d5bd3d"}, {"url": "https://git.kernel.org/stable/c/9d160b35cc34a2ba8229d07651468a7848325135"}], "title": "net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-64541", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T15:42:09.809089Z"}}}], "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": "2026-10-19T20:48:39.587Z"}}]}}

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-64541", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.795Z", "datePublished": "2026-07-27T20:10:34.439Z", "dateUpdated": "2026-10-19T20:48:39.587Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:57:17.774Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket\n\nsmc_cdc_rx_handler() looks up the connection by token under the link\ngroup's conns_lock, drops the lock, and then dereferences conn and the\nsmc_sock derived from it, ending in sock_hold(&smc->sk) inside\nsmc_cdc_msg_recv(). No reference is held across the lock release.\n\nThe only reference pinning the socket while the connection is\ndiscoverable in the link group is taken in smc_lgr_register_conn()\n(sock_hold) and dropped in __smc_lgr_unregister_conn() (sock_put), both\nunder conns_lock. Once the handler drops conns_lock, a concurrent\nclose() -> smc_release() -> smc_conn_free() -> smc_lgr_unregister_conn()\ncan drop that reference and free the smc_sock, so the handler's later\nsock_hold() runs on freed memory:\n\n WARNING: lib/refcount.c:25 at refcount_warn_saturate\n Workqueue: rxe_wq do_work\n refcount_warn_saturate (lib/refcount.c:25)\n smc_cdc_msg_recv (net/smc/smc_cdc.c:430)\n smc_cdc_rx_handler (net/smc/smc_cdc.c:502)\n smc_wr_rx_tasklet_fn (net/smc/smc_wr.c:445)\n tasklet_action_common (kernel/softirq.c:938)\n handle_softirqs (kernel/softirq.c:622)\n Kernel panic - not syncing: panic_on_warn set\n\nOnly SMC-R is affected. The SMC-D receive tasklet is stopped by\ntasklet_kill(&conn->rx_tsklet) in smc_conn_free() before the connection\nis unregistered, so it cannot run concurrently with the free.\n\nTake the socket reference while still holding conns_lock, so the\nregistration reference can no longer be the last one, and drop it once\nthe handler is done."}], "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 vulnerable handler is driven entirely by a CDC control message sent by the remote SMC-R peer over the RDMA link, with an attacker-chosen `token` field and no local syscall involvement. SMC-R runs over RoCEv2 (IP/UDP-routable, port 4791) with the CLC handshake over plain TCP, and SMC-Rv2 explicitly supports non-local/routed peers, so the attacker need not share an L2 segment.\nAC:L - The attacker controls both sides of the race: it chooses when to emit CDC messages and which connection to target (the alert token is disclosed to it in the CLC accept/confirm), and it can drive the teardown side itself via CDC close/abort flags into `smc_close_passive_work()` or a stale seqno with `failover_validation` into `abort_work` -> `smc_conn_kill()`. The race can be retried indefinitely across many connections in the same link group, and was reproduced in practice with soft-RoCE.\nPR:N - Establishing an SMC-R connection to a listening SMC socket requires no credentials \u2014 SMC has no authentication layer of its own, exactly like plain TCP. Everything after connection establishment (sending CDC messages with a chosen token, signalling close/abort) is available to an unauthenticated peer.\nUI:N - The CDC message is processed in a softirq tasklet from the RDMA completion queue with no involvement from any local user or application action. No victim interaction of any kind is needed.\nS:U - The corruption is confined to kernel memory within the same security authority; there is no VM, IOMMU, or sandbox boundary crossed. This is a standard in-kernel use-after-free.\nC:H - The freed `smc_sock` is reused type-safely as another live socket, so attacker-supplied cursors applied by `smc_cdc_msg_recv_action()` break the `0 <= bytes_to_rcv <= rmb_desc->len` invariant and make `smc_rx_recvmsg()` hand stale RMB contents to userspace, while the urgent-data path reads `*(base + conn->urg_curs.count - 1)` at an attacker-chosen offset. Once the slab page is reclaimed after the RCU grace period, reuse is unconstrained, giving a general kernel-memory read primitive.\nI:H - `sock_hold()` on an already-zero refcount followed by `sock_put()` re-enters `sk_free()`, yielding a double free, and the handler additionally writes `sk_err`/`sk_shutdown`, makes indirect calls through `sk_data_ready()`/`sk_write_space()`, and `queue_work()`s a freed `work_struct`. These are classic heap-spray and control-flow-hijack primitives leading to arbitrary kernel write.\nA:H - The reported symptom is `refcount_warn_saturate` from `smc_cdc_msg_recv()`, which is an immediate kernel panic on `panic_on_warn` systems, and dereferencing freed memory in softirq context otherwise oopses. The attacker can trigger it repeatedly without authentication."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/smc/smc_cdc.c"], "versions": [{"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "8de4f665d0febfb92803dece377791a563fc7041", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "8145b432136285e01091815b48ceb2dae261f262", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "1951bffbc6493ec34cff3956b29d4bc6606904a6", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "647b19e5cc145a2f1f685ae8ff3805a17356888c", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "472e9d7c0d5b03be3ff91ff941f57da822b031bc", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "3bfb96d9bc6a7ed0b99c7db329cc2e22a28d84bb", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "ce5aa8084329351086894aa34d77e40301d5bd3d", "status": "affected", "versionType": "git"}, {"version": "d7b0e37c1ac152905b18a5b9506179091a35b0b6", "lessThan": "9d160b35cc34a2ba8229d07651468a7848325135", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/smc/smc_cdc.c"], "versions": [{"version": "4.18", "status": "affected"}, {"version": "0", "lessThan": "4.18", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "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": "4.18", "versionEndExcluding": "5.10.261"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "5.15.212"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.1.178"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.6.145"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.12.97"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.18.40"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/8de4f665d0febfb92803dece377791a563fc7041"}, {"url": "https://git.kernel.org/stable/c/8145b432136285e01091815b48ceb2dae261f262"}, {"url": "https://git.kernel.org/stable/c/1951bffbc6493ec34cff3956b29d4bc6606904a6"}, {"url": "https://git.kernel.org/stable/c/647b19e5cc145a2f1f685ae8ff3805a17356888c"}, {"url": "https://git.kernel.org/stable/c/472e9d7c0d5b03be3ff91ff941f57da822b031bc"}, {"url": "https://git.kernel.org/stable/c/3bfb96d9bc6a7ed0b99c7db329cc2e22a28d84bb"}, {"url": "https://git.kernel.org/stable/c/ce5aa8084329351086894aa34d77e40301d5bd3d"}, {"url": "https://git.kernel.org/stable/c/9d160b35cc34a2ba8229d07651468a7848325135"}], "title": "net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-64541", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T15:42:09.809089Z"}}}], "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": "2026-10-16T15:42:10.459Z"}}]}}

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No reference is held across the lock release.\n\nThe only reference pinning the socket while the connection is\ndiscoverable in the link group is taken in smc_lgr_register_conn()\n(sock_hold) and dropped in __smc_lgr_unregister_conn() (sock_put), both\nunder conns_lock. Once the handler drops conns_lock, a concurrent\nclose() -> smc_release() -> smc_conn_free() -> smc_lgr_unregister_conn()\ncan drop that reference and free the smc_sock, so the handler's later\nsock_hold() runs on freed memory:\n\n WARNING: lib/refcount.c:25 at refcount_warn_saturate\n Workqueue: rxe_wq do_work\n refcount_warn_saturate (lib/refcount.c:25)\n smc_cdc_msg_recv (net/smc/smc_cdc.c:430)\n smc_cdc_rx_handler (net/smc/smc_cdc.c:502)\n smc_wr_rx_tasklet_fn (net/smc/smc_wr.c:445)\n tasklet_action_common (kernel/softirq.c:938)\n handle_softirqs (kernel/softirq.c:622)\n Kernel panic - not syncing: panic_on_warn set\n\nOnly SMC-R is affected. The SMC-D receive tasklet is stopped by\ntasklet_kill(&conn->rx_tsklet) in smc_conn_free() before the connection\nis unregistered, so it cannot run concurrently with the free.\n\nTake the socket reference while still holding conns_lock, so the\nregistration reference can no longer be the last one, and drop it once\nthe handler is done."}], "id": "CVE-2026-64541", "lastModified": "2026-11-13T18:26:37.570", "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"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-64541", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-16T15:42:09.809089Z", "version": "2.0.3"}}]}, "published": "2026-07-27T21:17:06.570", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/1951bffbc6493ec34cff3956b29d4bc6606904a6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/3bfb96d9bc6a7ed0b99c7db329cc2e22a28d84bb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/472e9d7c0d5b03be3ff91ff941f57da822b031bc"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/647b19e5cc145a2f1f685ae8ff3805a17356888c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/8145b432136285e01091815b48ceb2dae261f262"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/8de4f665d0febfb92803dece377791a563fc7041"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/9d160b35cc34a2ba8229d07651468a7848325135"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/ce5aa8084329351086894aa34d77e40301d5bd3d"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{"bugzilla": {"description": "kernel: net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket", "id": "2507721", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2507721"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-364", "details": ["No description is available for this CVE."], "name": "CVE-2026-64541", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "impact": "moderate", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "impact": "moderate", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "impact": "moderate", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "impact": "moderate", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "impact": "moderate", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "impact": "moderate", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "impact": "moderate", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "impact": "moderate", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-07-27T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-64541\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-64541\nhttps://lore.kernel.org/linux-cve-announce/2026072735-CVE-2026-64541-21ef@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[d7b0e37c1ac152905b18a5b9506179091a35b0b6,8de4f665d0febfb92803dece377791a563fc7041)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[d7b0e37c1ac152905b18a5b9506179091a35b0b6,8145b432136285e01091815b48ceb2dae261f262)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[d7b0e37c1ac152905b18a5b9506179091a35b0b6,1951bffbc6493ec34cff3956b29d4bc6606904a6)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[d7b0e37c1ac152905b18a5b9506179091a35b0b6,647b19e5cc145a2f1f685ae8ff3805a17356888c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[d7b0e37c1ac152905b18a5b9506179091a35b0b6,472e9d7c0d5b03be3ff91ff941f57da822b031bc)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[d7b0e37c1ac152905b18a5b9506179091a35b0b6,3bfb96d9bc6a7ed0b99c7db329cc2e22a28d84bb)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[d7b0e37c1ac152905b18a5b9506179091a35b0b6,ce5aa8084329351086894aa34d77e40301d5bd3d)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[d7b0e37c1ac152905b18a5b9506179091a35b0b6,9d160b35cc34a2ba8229d07651468a7848325135)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4.18"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,4.18)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.10.261,5.11.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.15.212,5.16.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.178,6.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.145,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.97,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.40,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.5,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2-rc3,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-07-28T03:15:07.797204+00:00", "updated": "2026-10-20T10:00:14.819834+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}