CVE-2026-97940

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-97940", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:18:58.204Z", "datePublished": "2026-09-25T10:22:52.936Z", "dateUpdated": "2026-10-19T09:11:06.854Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:11:06.854Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: fix fib6 walker UAF on seq stop\n\nipv6_route_iter_active() treats a walker in FWS_U at the table root as\nalready unlinked. fib6_del_route() can move a still-linked walker into\nthat same state when the current leaf is the last route at the root,\nso ipv6_route_native_seq_stop() skips fib6_walker_unlink(). The seq\nprivate object can then be freed while it remains on\nnet->ipv6.fib6_walkers. A later route deletion walks the dangling list\nand uses the freed walker.\n\nUse the list head as membership state and reinitialize it when\nunlinking. Keep the existing w->node check so a never-started iterator\nwith a zeroed private object is not treated as linked.\n\nThe same stop helper is used by /proc/net/ipv6_route and by the BPF\nipv6_route iterator. The BPF show path only widens the race."}], "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 bug is reached by a local read() of /proc/net/ipv6_route (ipv6_route_native_seq_stop via ipv6_route_seq_ops, or the BPF ipv6_route iterator) racing a local RTM_DELROUTE netlink request that runs fib6_del_route(). No remote protocol supplies data that causes the missed fib6_walker_unlink().\nAC:L - The attacker controls both sides of the race. One thread reads /proc/net/ipv6_route while another repeatedly adds and deletes the last route in the table root (e.g. ::/0), which moves the linked walker to FWS_U at the root so seq_stop skips the unlink. The attempt can be retried freely.\nPR:L - /proc/net/ipv6_route is created with mode 0 (0444, world-readable). Deleting routes needs CAP_NET_ADMIN only over the namespace, which an unprivileged user gets with unshare -Urn, and net->ipv6.fib6_walkers is per-namespace, so the whole attack runs in an attacker-owned netns.\nUI:N - No victim action is needed. The attacker opens, reads and closes the proc file and issues the route deletions themselves.\nS:U - The use-after-free happens in kernel heap memory and gives kernel-level impact within the same security authority. No VM or hardware isolation boundary is crossed.\nC:H - The freed seq_file private object (struct ipv6_route_iter, holding the fib6_walker) stays on net->ipv6.fib6_walkers. Later FOR_WALKERS loops read w->state, w->leaf and w->node from memory the attacker can reallocate with controlled contents, a UAF usable for kernel memory disclosure.\nI:H - fib6_del_route() and fib6_repair_tree() write w->leaf, w->state and w->node into the freed walker, and list_add/list_del on w->lh write pointers into it. That is a write primitive into a reallocated kernel heap object, usable for corruption and privilege escalation.\nA:H - Any later route deletion or tree repair in that namespace walks the dangling fib6_walkers entry, which causes list corruption or a KASAN/oops crash of the kernel."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/ipv6/ip6_fib.c"], "versions": [{"version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "lessThan": "9a3f73d62c86271614eda4c43315230896a37018", "status": "affected", "versionType": "git"}, {"version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "lessThan": "63407cddabc5992b5ac03af165559f4a1968a032", "status": "affected", "versionType": "git"}, {"version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "lessThan": "05b687ee04f816658f4a9cf586f4d2f129157943", "status": "affected", "versionType": "git"}, {"version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "lessThan": "14fdaba201fdff92a3e45994e02bccda409cb19d", "status": "affected", "versionType": "git"}, {"version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "lessThan": "0eede1689610e9eeaf729ba86fd1321799eb91a0", "status": "affected", "versionType": "git"}, {"version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "lessThan": "b89b691dd00bf39b9ba39ab9446f8c62f419fa7b", "status": "affected", "versionType": "git"}, {"version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "lessThan": "4553cfafa8d05c4ce20b1d18f79d9bb3b303fc02", "status": "affected", "versionType": "git"}, {"version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "lessThan": "19b4ed644d68098cc62ab612727f40d30f43476c", "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/ipv6/ip6_fib.c"], "versions": [{"version": "3.13", "status": "affected"}, {"version": "0", "lessThan": "3.13", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.271", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.222", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.189", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.158", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.111", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.53", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.7", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "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": "3.13", "versionEndExcluding": "5.10.271"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "5.15.222"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "6.1.189"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "6.6.158"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "6.12.111"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "6.18.53"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "7.2.7"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/9a3f73d62c86271614eda4c43315230896a37018"}, {"url": "https://git.kernel.org/stable/c/63407cddabc5992b5ac03af165559f4a1968a032"}, {"url": "https://git.kernel.org/stable/c/05b687ee04f816658f4a9cf586f4d2f129157943"}, {"url": "https://git.kernel.org/stable/c/14fdaba201fdff92a3e45994e02bccda409cb19d"}, {"url": "https://git.kernel.org/stable/c/0eede1689610e9eeaf729ba86fd1321799eb91a0"}, {"url": "https://git.kernel.org/stable/c/b89b691dd00bf39b9ba39ab9446f8c62f419fa7b"}, {"url": "https://git.kernel.org/stable/c/4553cfafa8d05c4ce20b1d18f79d9bb3b303fc02"}, {"url": "https://git.kernel.org/stable/c/19b4ed644d68098cc62ab612727f40d30f43476c"}], "title": "ipv6: fix fib6 walker UAF on seq stop", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/ipv6/ip6_fib.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "9a3f73d62c86271614eda4c43315230896a37018", "status": "affected", "version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "versionType": "git"}, {"lessThan": "63407cddabc5992b5ac03af165559f4a1968a032", "status": "affected", "version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "versionType": "git"}, {"lessThan": "05b687ee04f816658f4a9cf586f4d2f129157943", "status": "affected", "version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "versionType": "git"}, {"lessThan": "14fdaba201fdff92a3e45994e02bccda409cb19d", "status": "affected", "version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "versionType": "git"}, {"lessThan": "0eede1689610e9eeaf729ba86fd1321799eb91a0", "status": "affected", "version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "versionType": "git"}, {"lessThan": "b89b691dd00bf39b9ba39ab9446f8c62f419fa7b", "status": "affected", "version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "versionType": "git"}, {"lessThan": "4553cfafa8d05c4ce20b1d18f79d9bb3b303fc02", "status": "affected", "version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "versionType": "git"}, {"lessThan": "19b4ed644d68098cc62ab612727f40d30f43476c", "status": "affected", "version": "8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/ipv6/ip6_fib.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "3.13"}, {"lessThan": "3.13", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.271", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.222", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.189", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.158", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.111", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.53", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.7", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "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\nipv6: fix fib6 walker UAF on seq stop\n\nipv6_route_iter_active() treats a walker in FWS_U at the table root as\nalready unlinked. fib6_del_route() can move a still-linked walker into\nthat same state when the current leaf is the last route at the root,\nso ipv6_route_native_seq_stop() skips fib6_walker_unlink(). The seq\nprivate object can then be freed while it remains on\nnet->ipv6.fib6_walkers. A later route deletion walks the dangling list\nand uses the freed walker.\n\nUse the list head as membership state and reinitialize it when\nunlinking. Keep the existing w->node check so a never-started iterator\nwith a zeroed private object is not treated as linked.\n\nThe same stop helper is used by /proc/net/ipv6_route and by the BPF\nipv6_route iterator. The BPF show path only widens the race."}], "id": "CVE-2026-97940", "lastModified": "2026-10-19T10:17:45.110", "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"}]}, "published": "2026-09-25T11:17:21.410", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/05b687ee04f816658f4a9cf586f4d2f129157943"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0eede1689610e9eeaf729ba86fd1321799eb91a0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/14fdaba201fdff92a3e45994e02bccda409cb19d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/19b4ed644d68098cc62ab612727f40d30f43476c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4553cfafa8d05c4ce20b1d18f79d9bb3b303fc02"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/63407cddabc5992b5ac03af165559f4a1968a032"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9a3f73d62c86271614eda4c43315230896a37018"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b89b691dd00bf39b9ba39ab9446f8c62f419fa7b"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: ipv6: fix fib6 walker UAF on seq stop", "id": "2541042", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2541042"}, "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": "draft"}, "cwe": "CWE-825", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nipv6: fix fib6 walker UAF on seq stop\nipv6_route_iter_active() treats a walker in FWS_U at the table root as\nalready unlinked. fib6_del_route() can move a still-linked walker into\nthat same state when the current leaf is the last route at the root,\nso ipv6_route_native_seq_stop() skips fib6_walker_unlink(). The seq\nprivate object can then be freed while it remains on\nnet->ipv6.fib6_walkers. A later route deletion walks the dangling list\nand uses the freed walker.\nUse the list head as membership state and reinitialize it when\nunlinking. Keep the existing w->node check so a never-started iterator\nwith a zeroed private object is not treated as linked.\nThe same stop helper is used by /proc/net/ipv6_route and by the BPF\nipv6_route iterator. The BPF show path only widens the race.", "A flaw was found in the Linux kernel's IPv6 routing subsystem. A race condition during route iteration termination can allow an internal routing table walker structure to remain on an active list after its associated memory is released. A local user could exploit this flaw during concurrent route deletions, triggering a use-after-free condition that can result in a Denial of Service (DoS) via a system crash or potential privilege escalation."], "name": "CVE-2026-97940", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"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": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "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:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-09-25T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-97940\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-97940\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97940.mbox"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7,0eede1689610e9eeaf729ba86fd1321799eb91a0)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7,b89b691dd00bf39b9ba39ab9446f8c62f419fa7b)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7,4553cfafa8d05c4ce20b1d18f79d9bb3b303fc02)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7,19b4ed644d68098cc62ab612727f40d30f43476c)"}}], "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": "3.13"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,3.13)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.12.111,6.12.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.18.53,6.18.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2.7,7.2.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3-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": "2026-09-25T14:00:13.791681+00:00", "updated": "2026-10-01T08:00:04.587117+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}