CVE-2026-68398

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-68398", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.389Z", "datePublished": "2026-08-10T12:04:17.771Z", "dateUpdated": "2026-10-19T21:09:08.443Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:34:49.839Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nppp: defer channel free to an RCU grace period to fix pppol2tp RX UAF\n\npppol2tp_recv() runs in the L2TP UDP-encap softirq RX path:\n\n l2tp_udp_encap_recv() -> l2tp_recv_common() -> pppol2tp_recv()\n -> ppp_input(&po->chan)\n\nIt runs under rcu_read_lock() holding only an l2tp_session reference and\ntakes NO reference on the internal PPP channel (struct channel,\nchan->ppp) that ppp_input() dereferences.\n\nThe pppox socket is SOCK_RCU_FREE, so 'po' and the embedded ppp_channel\nare RCU-safe. But the internal struct channel is a separate allocation\nthat ppp_release_channel() frees with a plain kfree():\n\n close(data socket) -> pppol2tp_release() -> pppox_unbind_sock()\n -> ppp_unregister_channel() -> ppp_release_channel() -> kfree(pch)\n\nFor a channel that is bound (PPPIOCGCHAN) but not attached to a ppp unit\n(no PPPIOCCONNECT, pch->ppp == NULL) and not bridged, teardown skips\nboth ppp_disconnect_channel()'s synchronize_net() and\nppp_unbridge_channels()'s synchronize_rcu(), so the kfree() has no grace\nperiod. rcu_read_lock() in pppol2tp_recv() does not protect against a\nplain kfree(), so an in-flight ppp_input() on one CPU can dereference\nthe channel just freed by close() on another CPU.\n\nThe bug is reachable by an unprivileged user.\n\nDefer the channel free to an RCU callback via call_rcu() so the grace\nperiod fences any in-flight ppp_input(). The disconnect and unbridge\nteardown paths already fence with synchronize_net()/synchronize_rcu();\ncall_rcu() does the same here without stalling the close() path."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The free side of the race is a local close() of the pppol2tp socket, which no remote peer can invoke; the full attack (create tunnel/session via AF_PPPOX socket, drive RX with loopback UDP datagrams, close concurrently) is performed entirely through local syscalls.\nAC:L - The attacker controls both sides of the race, feeding the UDP-encap RX softirq from one thread while closing the pppox socket on another, and can retry the loop indefinitely until the window is hit.\nPR:L - No capability check exists on this path: pppox_create()/pppol2tp_connect() and ppp_register_net_channel() need no CAP_NET_ADMIN, and PPPIOCGCHAN is handled by pppox_ioctl() on the socket itself, so /dev/ppp access is not required; the fix commit states the bug is reachable by an unprivileged user.\nUI:N - The attacker performs every step \u2014 socket creation, session setup, packet injection and close() \u2014 with no action by any other user or administrator.\nS:U - The use-after-free corrupts kernel slab memory within the same kernel security authority; no VM, IOMMU or sandbox boundary is crossed.\nC:H - After the channel is freed and its slab object reallocated, ppp_input() reads pch->bridge and pch->ppp from attacker-groomed memory and can route received frames to an arbitrary attacker-chosen structure, giving a path to disclosing kernel memory.\nI:H - skb_queue_tail(&pch->file.rq, skb) writes a linked-list insertion into the freed object and wake_up_interruptible(&pch->file.rwait) traverses a freed waitqueue, so heap grooming yields controlled writes and function-pointer traversal usable for privilege escalation.\nA:H - Dereferencing and writing to the kfree()d struct channel from softirq context reliably corrupts the slab and panics or oopses the kernel, and the race can be re-triggered at will."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/net/ppp/ppp_generic.c"], "versions": [{"version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "4e47f1ac188ece11d6fdabe44166a2776cc5bd4e", "status": "affected", "versionType": "git"}, {"version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "110b765744b147c63882f5e9cb12931c5dc8d85f", "status": "affected", "versionType": "git"}, {"version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "4bb84e964ff0fe0a171c965362de72f9820dbce9", "status": "affected", "versionType": "git"}, {"version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "3ab32218d7182705dae5c86f13925f458072da2c", "status": "affected", "versionType": "git"}, {"version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "c9574b8a8edeb4edd3ac6472c27ef7184bdb2baa", "status": "affected", "versionType": "git"}, {"version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "06213c85d8c0994f786c093b8b2a517987943ca6", "status": "affected", "versionType": "git"}, {"version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "ec4215683e47424c9c4762fd3c60f552a3119142", "status": "affected", "versionType": "git"}, {"version": "d36e5ba7bbed5d7bd26e8609ffed503c2def401b", "status": "affected", "versionType": "git"}, {"version": "9bcc0508576b2d50efd958f2ea1c5906749c2c89", "status": "affected", "versionType": "git"}, {"version": "c2984681fe15cfb803a9132aaaf1140ab20a72c1", "status": "affected", "versionType": "git"}, {"version": "5803ecd7f6ac6f747582e775caa62ac9d0489261", "status": "affected", "versionType": "git"}, {"version": "26f8819ddd10141ebe7bbce700fbab36bfa5f478", "status": "affected", "versionType": "git"}, {"version": "3.2.99", "lessThan": "3.3", "status": "affected", "versionType": "semver"}, {"version": "3.16.54", "lessThan": "3.17", "status": "affected", "versionType": "semver"}, {"version": "4.4.225", "lessThan": "4.5", "status": "affected", "versionType": "semver"}, {"version": "4.9.225", "lessThan": "4.10", "status": "affected", "versionType": "semver"}, {"version": "4.14.182", "lessThan": "4.15", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/net/ppp/ppp_generic.c"], "versions": [{"version": "4.15", "status": "affected"}, {"version": "0", "lessThan": "4.15", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.216", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.148", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.101", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.6", "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": "4.15", "versionEndExcluding": "5.15.216"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.1.183"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.6.148"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.12.101"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.18.42"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "7.1.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "7.2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2.99"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.16.54"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4.225"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9.225"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14.182"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/4e47f1ac188ece11d6fdabe44166a2776cc5bd4e"}, {"url": "https://git.kernel.org/stable/c/110b765744b147c63882f5e9cb12931c5dc8d85f"}, {"url": "https://git.kernel.org/stable/c/4bb84e964ff0fe0a171c965362de72f9820dbce9"}, {"url": "https://git.kernel.org/stable/c/3ab32218d7182705dae5c86f13925f458072da2c"}, {"url": "https://git.kernel.org/stable/c/c9574b8a8edeb4edd3ac6472c27ef7184bdb2baa"}, {"url": "https://git.kernel.org/stable/c/06213c85d8c0994f786c093b8b2a517987943ca6"}, {"url": "https://git.kernel.org/stable/c/ec4215683e47424c9c4762fd3c60f552a3119142"}], "title": "ppp: defer channel free to an RCU grace period to fix pppol2tp RX UAF", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-68398", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T15:48:09.975001Z"}}}], "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": "2026-10-19T21:09:08.443Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-68398", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T15:48:09.975001Z"}}}], "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": "2026-10-16T15:48:10.741Z"}}], "cna": {"title": "ppp: defer channel free to an RCU grace period to fix pppol2tp RX UAF", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 7.8, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "AV:L - The free side of the race is a local close() of the pppol2tp socket, which no remote peer can invoke; the full attack (create tunnel/session via AF_PPPOX socket, drive RX with loopback UDP datagrams, close concurrently) is performed entirely through local syscalls.\nAC:L - The attacker controls both sides of the race, feeding the UDP-encap RX softirq from one thread while closing the pppox socket on another, and can retry the loop indefinitely until the window is hit.\nPR:L - No capability check exists on this path: pppox_create()/pppol2tp_connect() and ppp_register_net_channel() need no CAP_NET_ADMIN, and PPPIOCGCHAN is handled by pppox_ioctl() on the socket itself, so /dev/ppp access is not required; the fix commit states the bug is reachable by an unprivileged user.\nUI:N - The attacker performs every step \u2014 socket creation, session setup, packet injection and close() \u2014 with no action by any other user or administrator.\nS:U - The use-after-free corrupts kernel slab memory within the same kernel security authority; no VM, IOMMU or sandbox boundary is crossed.\nC:H - After the channel is freed and its slab object reallocated, ppp_input() reads pch->bridge and pch->ppp from attacker-groomed memory and can route received frames to an arbitrary attacker-chosen structure, giving a path to disclosing kernel memory.\nI:H - skb_queue_tail(&pch->file.rq, skb) writes a linked-list insertion into the freed object and wake_up_interruptible(&pch->file.rwait) traverses a freed waitqueue, so heap grooming yields controlled writes and function-pointer traversal usable for privilege escalation.\nA:H - Dereferencing and writing to the kfree()d struct channel from softirq context reliably corrupts the slab and panics or oopses the kernel, and the race can be re-triggered at will."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "4e47f1ac188ece11d6fdabe44166a2776cc5bd4e", "versionType": "git"}, {"status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "110b765744b147c63882f5e9cb12931c5dc8d85f", "versionType": "git"}, {"status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "4bb84e964ff0fe0a171c965362de72f9820dbce9", "versionType": "git"}, {"status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "3ab32218d7182705dae5c86f13925f458072da2c", "versionType": "git"}, {"status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "c9574b8a8edeb4edd3ac6472c27ef7184bdb2baa", "versionType": "git"}, {"status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "06213c85d8c0994f786c093b8b2a517987943ca6", "versionType": "git"}, {"status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "lessThan": "ec4215683e47424c9c4762fd3c60f552a3119142", "versionType": "git"}, {"status": "affected", "version": "d36e5ba7bbed5d7bd26e8609ffed503c2def401b", "versionType": "git"}, {"status": "affected", "version": "9bcc0508576b2d50efd958f2ea1c5906749c2c89", "versionType": "git"}, {"status": "affected", "version": "c2984681fe15cfb803a9132aaaf1140ab20a72c1", "versionType": "git"}, {"status": "affected", "version": "5803ecd7f6ac6f747582e775caa62ac9d0489261", "versionType": "git"}, {"status": "affected", "version": "26f8819ddd10141ebe7bbce700fbab36bfa5f478", "versionType": "git"}, {"status": "affected", "version": "3.2.99", "lessThan": "3.3", "versionType": "semver"}, {"status": "affected", "version": "3.16.54", "lessThan": "3.17", "versionType": "semver"}, {"status": "affected", "version": "4.4.225", "lessThan": "4.5", "versionType": "semver"}, {"status": "affected", "version": "4.9.225", "lessThan": "4.10", "versionType": "semver"}, {"status": "affected", "version": "4.14.182", "lessThan": "4.15", "versionType": "semver"}], "programFiles": ["drivers/net/ppp/ppp_generic.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "4.15"}, {"status": "unaffected", "version": "0", "lessThan": "4.15", "versionType": "semver"}, {"status": "unaffected", "version": "5.15.216", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.183", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.148", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.101", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.42", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.1.6", "versionType": "semver", "lessThanOrEqual": "7.1.*"}, {"status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["drivers/net/ppp/ppp_generic.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/4e47f1ac188ece11d6fdabe44166a2776cc5bd4e"}, {"url": "https://git.kernel.org/stable/c/110b765744b147c63882f5e9cb12931c5dc8d85f"}, {"url": "https://git.kernel.org/stable/c/4bb84e964ff0fe0a171c965362de72f9820dbce9"}, {"url": "https://git.kernel.org/stable/c/3ab32218d7182705dae5c86f13925f458072da2c"}, {"url": "https://git.kernel.org/stable/c/c9574b8a8edeb4edd3ac6472c27ef7184bdb2baa"}, {"url": "https://git.kernel.org/stable/c/06213c85d8c0994f786c093b8b2a517987943ca6"}, {"url": "https://git.kernel.org/stable/c/ec4215683e47424c9c4762fd3c60f552a3119142"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nppp: defer channel free to an RCU grace period to fix pppol2tp RX UAF\n\npppol2tp_recv() runs in the L2TP UDP-encap softirq RX path:\n\n l2tp_udp_encap_recv() -> l2tp_recv_common() -> pppol2tp_recv()\n -> ppp_input(&po->chan)\n\nIt runs under rcu_read_lock() holding only an l2tp_session reference and\ntakes NO reference on the internal PPP channel (struct channel,\nchan->ppp) that ppp_input() dereferences.\n\nThe pppox socket is SOCK_RCU_FREE, so 'po' and the embedded ppp_channel\nare RCU-safe. But the internal struct channel is a separate allocation\nthat ppp_release_channel() frees with a plain kfree():\n\n close(data socket) -> pppol2tp_release() -> pppox_unbind_sock()\n -> ppp_unregister_channel() -> ppp_release_channel() -> kfree(pch)\n\nFor a channel that is bound (PPPIOCGCHAN) but not attached to a ppp unit\n(no PPPIOCCONNECT, pch->ppp == NULL) and not bridged, teardown skips\nboth ppp_disconnect_channel()'s synchronize_net() and\nppp_unbridge_channels()'s synchronize_rcu(), so the kfree() has no grace\nperiod. rcu_read_lock() in pppol2tp_recv() does not protect against a\nplain kfree(), so an in-flight ppp_input() on one CPU can dereference\nthe channel just freed by close() on another CPU.\n\nThe bug is reachable by an unprivileged user.\n\nDefer the channel free to an RCU callback via call_rcu() so the grace\nperiod fences any in-flight ppp_input(). The disconnect and unbridge\nteardown paths already fence with synchronize_net()/synchronize_rcu();\ncall_rcu() does the same here without stalling the close() path."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.216", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.183", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.148", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.101", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.18.42", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.1.6", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.2", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "3.2.99"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "3.16.54"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "4.4.225"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "4.9.225"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "4.14.182"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:34:49.839Z"}}}, "cveMetadata": {"cveId": "CVE-2026-68398", "state": "PUBLISHED", "dateUpdated": "2026-10-19T21:09:08.443Z", "dateReserved": "2026-07-30T09:28:09.389Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2026-08-10T12:04:17.771Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/net/ppp/ppp_generic.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "4e47f1ac188ece11d6fdabe44166a2776cc5bd4e", "status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "versionType": "git"}, {"lessThan": "110b765744b147c63882f5e9cb12931c5dc8d85f", "status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "versionType": "git"}, {"lessThan": "4bb84e964ff0fe0a171c965362de72f9820dbce9", "status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "versionType": "git"}, {"lessThan": "3ab32218d7182705dae5c86f13925f458072da2c", "status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "versionType": "git"}, {"lessThan": "c9574b8a8edeb4edd3ac6472c27ef7184bdb2baa", "status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "versionType": "git"}, {"lessThan": "06213c85d8c0994f786c093b8b2a517987943ca6", "status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "versionType": "git"}, {"lessThan": "ec4215683e47424c9c4762fd3c60f552a3119142", "status": "affected", "version": "ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741", "versionType": "git"}, {"status": "affected", "version": "d36e5ba7bbed5d7bd26e8609ffed503c2def401b", "versionType": "git"}, {"status": "affected", "version": "9bcc0508576b2d50efd958f2ea1c5906749c2c89", "versionType": "git"}, {"status": "affected", "version": "c2984681fe15cfb803a9132aaaf1140ab20a72c1", "versionType": "git"}, {"status": "affected", "version": "5803ecd7f6ac6f747582e775caa62ac9d0489261", "versionType": "git"}, {"status": "affected", "version": "26f8819ddd10141ebe7bbce700fbab36bfa5f478", "versionType": "git"}, {"lessThan": "3.3", "status": "affected", "version": "3.2.99", "versionType": "semver"}, {"lessThan": "3.17", "status": "affected", "version": "3.16.54", "versionType": "semver"}, {"lessThan": "4.5", "status": "affected", "version": "4.4.225", "versionType": "semver"}, {"lessThan": "4.10", "status": "affected", "version": "4.9.225", "versionType": "semver"}, {"lessThan": "4.15", "status": "affected", "version": "4.14.182", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/net/ppp/ppp_generic.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.15"}, {"lessThan": "4.15", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.216", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.183", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.148", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.101", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.42", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.6", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nppp: defer channel free to an RCU grace period to fix pppol2tp RX UAF\n\npppol2tp_recv() runs in the L2TP UDP-encap softirq RX path:\n\n l2tp_udp_encap_recv() -> l2tp_recv_common() -> pppol2tp_recv()\n -> ppp_input(&po->chan)\n\nIt runs under rcu_read_lock() holding only an l2tp_session reference and\ntakes NO reference on the internal PPP channel (struct channel,\nchan->ppp) that ppp_input() dereferences.\n\nThe pppox socket is SOCK_RCU_FREE, so 'po' and the embedded ppp_channel\nare RCU-safe. But the internal struct channel is a separate allocation\nthat ppp_release_channel() frees with a plain kfree():\n\n close(data socket) -> pppol2tp_release() -> pppox_unbind_sock()\n -> ppp_unregister_channel() -> ppp_release_channel() -> kfree(pch)\n\nFor a channel that is bound (PPPIOCGCHAN) but not attached to a ppp unit\n(no PPPIOCCONNECT, pch->ppp == NULL) and not bridged, teardown skips\nboth ppp_disconnect_channel()'s synchronize_net() and\nppp_unbridge_channels()'s synchronize_rcu(), so the kfree() has no grace\nperiod. rcu_read_lock() in pppol2tp_recv() does not protect against a\nplain kfree(), so an in-flight ppp_input() on one CPU can dereference\nthe channel just freed by close() on another CPU.\n\nThe bug is reachable by an unprivileged user.\n\nDefer the channel free to an RCU callback via call_rcu() so the grace\nperiod fences any in-flight ppp_input(). The disconnect and unbridge\nteardown paths already fence with synchronize_net()/synchronize_rcu();\ncall_rcu() does the same here without stalling the close() path."}], "id": "CVE-2026-68398", "lastModified": "2026-10-19T22:17:17.243", "metrics": {"cvssMetricV31": [{"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": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-68398", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-16T15:48:09.975001Z", "version": "2.0.3"}}]}, "published": "2026-08-10T13:20:33.243", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/06213c85d8c0994f786c093b8b2a517987943ca6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/110b765744b147c63882f5e9cb12931c5dc8d85f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/3ab32218d7182705dae5c86f13925f458072da2c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4bb84e964ff0fe0a171c965362de72f9820dbce9"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4e47f1ac188ece11d6fdabe44166a2776cc5bd4e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c9574b8a8edeb4edd3ac6472c27ef7184bdb2baa"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ec4215683e47424c9c4762fd3c60f552a3119142"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{"bugzilla": {"description": "kernel: Linux kernel: PPP over L2TP Use-After-Free vulnerability", "id": "2513188", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2513188"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.7", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nppp: defer channel free to an RCU grace period to fix pppol2tp RX UAF\npppol2tp_recv() runs in the L2TP UDP-encap softirq RX path:\nl2tp_udp_encap_recv() -> l2tp_recv_common() -> pppol2tp_recv()\n-> ppp_input(&po->chan)\nIt runs under rcu_read_lock() holding only an l2tp_session reference and\ntakes NO reference on the internal PPP channel (struct channel,\nchan->ppp) that ppp_input() dereferences.\nThe pppox socket is SOCK_RCU_FREE, so 'po' and the embedded ppp_channel\nare RCU-safe. But the internal struct channel is a separate allocation\nthat ppp_release_channel() frees with a plain kfree():\nclose(data socket) -> pppol2tp_release() -> pppox_unbind_sock()\n-> ppp_unregister_channel() -> ppp_release_channel() -> kfree(pch)\nFor a channel that is bound (PPPIOCGCHAN) but not attached to a ppp unit\n(no PPPIOCCONNECT, pch->ppp == NULL) and not bridged, teardown skips\nboth ppp_disconnect_channel()'s synchronize_net() and\nppp_unbridge_channels()'s synchronize_rcu(), so the kfree() has no grace\nperiod. rcu_read_lock() in pppol2tp_recv() does not protect against a\nplain kfree(), so an in-flight ppp_input() on one CPU can dereference\nthe channel just freed by close() on another CPU.\nThe bug is reachable by an unprivileged user.\nDefer the channel free to an RCU callback via call_rcu() so the grace\nperiod fences any in-flight ppp_input(). The disconnect and unbridge\nteardown paths already fence with synchronize_net()/synchronize_rcu();\ncall_rcu() does the same here without stalling the close() path.", "A flaw was found in the Linux kernel's Point-to-Point Protocol (PPP) over L2TP (Layer 2 Tunneling Protocol) implementation. An unprivileged user can exploit a Use-After-Free (UAF) vulnerability, where the system attempts to use memory after it has been freed. This can lead to memory corruption, potentially allowing an attacker to cause system instability or execute arbitrary code."], "name": "CVE-2026-68398", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "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": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:enterprise_linux_nvidia:", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux for NVIDIA 26"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-08-10T12:04:17Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-68398\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-68398\nhttps://git.kernel.org/stable/c/06213c85d8c0994f786c093b8b2a517987943ca6\nhttps://git.kernel.org/stable/c/3ab32218d7182705dae5c86f13925f458072da2c\nhttps://git.kernel.org/stable/c/4bb84e964ff0fe0a171c965362de72f9820dbce9\nhttps://git.kernel.org/stable/c/c9574b8a8edeb4edd3ac6472c27ef7184bdb2baa\nhttps://git.kernel.org/stable/c/ec4215683e47424c9c4762fd3c60f552a3119142"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741,4bb84e964ff0fe0a171c965362de72f9820dbce9)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741,3ab32218d7182705dae5c86f13925f458072da2c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741,c9574b8a8edeb4edd3ac6472c27ef7184bdb2baa)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741,06213c85d8c0994f786c093b8b2a517987943ca6)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741,ec4215683e47424c9c4762fd3c60f552a3119142)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[d36e5ba7bbed5d7bd26e8609ffed503c2def401b,*]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9bcc0508576b2d50efd958f2ea1c5906749c2c89,*]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[c2984681fe15cfb803a9132aaaf1140ab20a72c1,*]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[5803ecd7f6ac6f747582e775caa62ac9d0489261,*]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[26f8819ddd10141ebe7bbce700fbab36bfa5f478,*]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.2.99,3.3)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.16.54,3.17)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[4.4.225,4.5)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[4.9.225,4.10)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[4.14.182,4.15)"}}], "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": "4.15"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,4.15)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.148,6.6.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.101,6.12.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.42,6.18.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.6,7.1.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2-rc4,*]"}}], "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": "2026-08-10T16:15:04.434320+00:00", "updated": "2026-10-20T10:45:13.772172+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}