{"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": "2026-08-10T12:04:17.771Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-10T12:04:17.771Z"}, "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."}], "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": "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": "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-rc4", "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": "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-rc4"}, {"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/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"}}}}

{}

{"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": "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": "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-rc4", "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": "2026-08-10T13:20:33.243", "metrics": {}, "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/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/c9574b8a8edeb4edd3ac6472c27ef7184bdb2baa"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ec4215683e47424c9c4762fd3c60f552a3119142"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"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"}