{"api_version":"1","generated_at":"2026-08-15T16:27:34+00:00","cve":"CVE-2026-74561","urls":{"html":"https://cve.report/CVE-2026-74561","api":"https://cve.report/api/cve/CVE-2026-74561.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74561","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74561"},"summary":{"title":"nexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush\n\nnh_rt_cache_flush() walks nh->f6i_list during an RTNL-serialized nexthop\nreplace without holding nh->lock, racing the unlocked IPv6 route\nadd/delete that mutate the list under nh->lock and free fib6_info\nentries (nh_rt_cache_flush() is inlined into rtm_new_nexthop()):\n\n  BUG: KASAN: slab-use-after-free in nh_rt_cache_flush (net/ipv4/nexthop.c:2243)\n  Read of size 8 at addr ffff888012953e18 by task exploit/146\n   nh_rt_cache_flush (net/ipv4/nexthop.c:2243)\n   replace_nexthop (net/ipv4/nexthop.c:2610)\n   rtm_new_nexthop (net/ipv4/nexthop.c:3323)\n   rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n\nUnlike the other f6i_list walks, this one bumps each route's sernum via\nfib6_update_sernum_upto_root(), which needs tb6_lock; taking nh->lock\naround it would invert the established tb6_lock -> nh->lock order and\ndeadlock. As the only purpose is to invalidate cached dsts, bump the\nIPv6 sernum for the whole netns with rt_genid_bump_ipv6() instead,\nmirroring the rt_cache_flush() already done for IPv4 just above.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 13:18:01","updated_at":"2026-08-15 13:18:01"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/4787a6d2629b4e8c0b6bacab1f75c1660eca44d9","name":"https://git.kernel.org/stable/c/4787a6d2629b4e8c0b6bacab1f75c1660eca44d9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/44f53e4331a30fabc38a411fae7524341b618db3","name":"https://git.kernel.org/stable/c/44f53e4331a30fabc38a411fae7524341b618db3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74561","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74561","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 081efd18326e353c6fbfdeff903a83edde953f72 44f53e4331a30fabc38a411fae7524341b618db3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 081efd18326e353c6fbfdeff903a83edde953f72 4787a6d2629b4e8c0b6bacab1f75c1660eca44d9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.16","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.16 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.8 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc6 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/ipv4/nexthop.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"44f53e4331a30fabc38a411fae7524341b618db3","status":"affected","version":"081efd18326e353c6fbfdeff903a83edde953f72","versionType":"git"},{"lessThan":"4787a6d2629b4e8c0b6bacab1f75c1660eca44d9","status":"affected","version":"081efd18326e353c6fbfdeff903a83edde953f72","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv4/nexthop.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.16"},{"lessThan":"6.16","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.8","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc6","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.8","versionStartIncluding":"6.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc6","versionStartIncluding":"6.16","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush\n\nnh_rt_cache_flush() walks nh->f6i_list during an RTNL-serialized nexthop\nreplace without holding nh->lock, racing the unlocked IPv6 route\nadd/delete that mutate the list under nh->lock and free fib6_info\nentries (nh_rt_cache_flush() is inlined into rtm_new_nexthop()):\n\n  BUG: KASAN: slab-use-after-free in nh_rt_cache_flush (net/ipv4/nexthop.c:2243)\n  Read of size 8 at addr ffff888012953e18 by task exploit/146\n   nh_rt_cache_flush (net/ipv4/nexthop.c:2243)\n   replace_nexthop (net/ipv4/nexthop.c:2610)\n   rtm_new_nexthop (net/ipv4/nexthop.c:3323)\n   rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n\nUnlike the other f6i_list walks, this one bumps each route's sernum via\nfib6_update_sernum_upto_root(), which needs tb6_lock; taking nh->lock\naround it would invert the established tb6_lock -> nh->lock order and\ndeadlock. As the only purpose is to invalidate cached dsts, bump the\nIPv6 sernum for the whole netns with rt_genid_bump_ipv6() instead,\nmirroring the rt_cache_flush() already done for IPv4 just above."}],"providerMetadata":{"dateUpdated":"2026-08-15T12:28:04.525Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/44f53e4331a30fabc38a411fae7524341b618db3"},{"url":"https://git.kernel.org/stable/c/4787a6d2629b4e8c0b6bacab1f75c1660eca44d9"}],"title":"nexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74561","datePublished":"2026-08-15T12:28:04.525Z","dateReserved":"2026-08-15T05:44:03.916Z","dateUpdated":"2026-08-15T12:28:04.525Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 13:18:01","lastModifiedDate":"2026-08-15 13:18:01","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74561","Ordinal":"1","Title":"nexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush","CVE":"CVE-2026-74561","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74561","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush\n\nnh_rt_cache_flush() walks nh->f6i_list during an RTNL-serialized nexthop\nreplace without holding nh->lock, racing the unlocked IPv6 route\nadd/delete that mutate the list under nh->lock and free fib6_info\nentries (nh_rt_cache_flush() is inlined into rtm_new_nexthop()):\n\n  BUG: KASAN: slab-use-after-free in nh_rt_cache_flush (net/ipv4/nexthop.c:2243)\n  Read of size 8 at addr ffff888012953e18 by task exploit/146\n   nh_rt_cache_flush (net/ipv4/nexthop.c:2243)\n   replace_nexthop (net/ipv4/nexthop.c:2610)\n   rtm_new_nexthop (net/ipv4/nexthop.c:3323)\n   rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n\nUnlike the other f6i_list walks, this one bumps each route's sernum via\nfib6_update_sernum_upto_root(), which needs tb6_lock; taking nh->lock\naround it would invert the established tb6_lock -> nh->lock order and\ndeadlock. As the only purpose is to invalidate cached dsts, bump the\nIPv6 sernum for the whole netns with rt_genid_bump_ipv6() instead,\nmirroring the rt_cache_flush() already done for IPv4 just above.","Type":"Description","Title":"nexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush"}]}}}