{"id":"CVE-2026-74581","state":"PUBLISHED","title":"net: ipv6: clear suppressed fib6 rule result","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv6: clear suppressed fib6 rule result\n\nfib6_rule_suppress() drops a suppressed route with ip6_rt_put_flags(),\nbut leaves res->rt6 pointing at the released rt6_info.\n\nIf no later rule supplies a replacement, fib6_rule_lookup() still sees\nres.rt6 and returns that stale dst to its caller. A suppressing rule can\ntherefore leak a released route back to rt6_lookup(), and the next put\nhits rcuref_put_slowpath() from dst_release().\n\nClear res->rt6 when suppressing the route so suppressed lookups fall\nthrough to the null dst instead of reusing the released one.","publishedAt":"2026-08-21T16:31:54.683Z","updatedAt":"2026-10-16T19:05:58.061Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"209d35ee34e25f9668c404350a1c86d914c54ffa","status":"affected","lessThan":"90c57310e266eb94e4a80d6b15a9ca131d2e82cb","versionType":"git"},{"version":"8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383","status":"affected","lessThan":"5d29b286c9de0b309e94b9ed083aa1a2f429434f","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"354db6243eca59e9d187ffbf8b7955b044ce84dc","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"6d98c70fe0ba8c7708bfd5b2a5174d2086775daa","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"9bad152c42b37499162367fe47867411e62fffa3","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"dc3ab04220667f254f4348572b2a0b3febff89fb","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"a341c091ca0bfae377747b1b59a3bd8ebe18a937","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"6aea62e433fe1b586202a5fee8b5807ce635e1d7","versionType":"git"},{"version":"ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29","status":"affected","versionType":"git"},{"version":"5.10.84","status":"affected","lessThan":"5.10.265","versionType":"semver"},{"version":"5.15.7","status":"affected","lessThan":"5.15.216","versionType":"semver"},{"version":"5.4.164","status":"affected","lessThan":"5.5","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/fib6_rules.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.16","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.151","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.103","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/fib6_rules.c"]}],"references":["https://git.kernel.org/stable/c/90c57310e266eb94e4a80d6b15a9ca131d2e82cb","https://git.kernel.org/stable/c/5d29b286c9de0b309e94b9ed083aa1a2f429434f","https://git.kernel.org/stable/c/354db6243eca59e9d187ffbf8b7955b044ce84dc","https://git.kernel.org/stable/c/6d98c70fe0ba8c7708bfd5b2a5174d2086775daa","https://git.kernel.org/stable/c/9bad152c42b37499162367fe47867411e62fffa3","https://git.kernel.org/stable/c/dc3ab04220667f254f4348572b2a0b3febff89fb","https://git.kernel.org/stable/c/a341c091ca0bfae377747b1b59a3bd8ebe18a937","https://git.kernel.org/stable/c/6aea62e433fe1b586202a5fee8b5807ce635e1d7"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74581.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74581","state":"PUBLISHED","datePublished":"2026-08-21T16:31:54.683Z","dateUpdated":"2026-10-16T19:05:58.061Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.918Z"},"containers":{"cna":{"title":"net: ipv6: clear suppressed fib6 rule result","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv6: clear suppressed fib6 rule result\n\nfib6_rule_suppress() drops a suppressed route with ip6_rt_put_flags(),\nbut leaves res->rt6 pointing at the released rt6_info.\n\nIf no later rule supplies a replacement, fib6_rule_lookup() still sees\nres.rt6 and returns that stale dst to its caller. A suppressing rule can\ntherefore leak a released route back to rt6_lookup(), and the next put\nhits rcuref_put_slowpath() from dst_release().\n\nClear res->rt6 when suppressing the route so suppressed lookups fall\nthrough to the null dst instead of reusing the released one."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"209d35ee34e25f9668c404350a1c86d914c54ffa","status":"affected","lessThan":"90c57310e266eb94e4a80d6b15a9ca131d2e82cb","versionType":"git"},{"version":"8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383","status":"affected","lessThan":"5d29b286c9de0b309e94b9ed083aa1a2f429434f","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"354db6243eca59e9d187ffbf8b7955b044ce84dc","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"6d98c70fe0ba8c7708bfd5b2a5174d2086775daa","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"9bad152c42b37499162367fe47867411e62fffa3","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"dc3ab04220667f254f4348572b2a0b3febff89fb","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"a341c091ca0bfae377747b1b59a3bd8ebe18a937","versionType":"git"},{"version":"cdef485217d30382f3bf6448c54b4401648fe3f1","status":"affected","lessThan":"6aea62e433fe1b586202a5fee8b5807ce635e1d7","versionType":"git"},{"version":"ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29","status":"affected","versionType":"git"},{"version":"5.10.84","status":"affected","lessThan":"5.10.265","versionType":"semver"},{"version":"5.15.7","status":"affected","lessThan":"5.15.216","versionType":"semver"},{"version":"5.4.164","status":"affected","lessThan":"5.5","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/fib6_rules.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.16","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.151","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.103","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/fib6_rules.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/90c57310e266eb94e4a80d6b15a9ca131d2e82cb"},{"url":"https://git.kernel.org/stable/c/5d29b286c9de0b309e94b9ed083aa1a2f429434f"},{"url":"https://git.kernel.org/stable/c/354db6243eca59e9d187ffbf8b7955b044ce84dc"},{"url":"https://git.kernel.org/stable/c/6d98c70fe0ba8c7708bfd5b2a5174d2086775daa"},{"url":"https://git.kernel.org/stable/c/9bad152c42b37499162367fe47867411e62fffa3"},{"url":"https://git.kernel.org/stable/c/dc3ab04220667f254f4348572b2a0b3febff89fb"},{"url":"https://git.kernel.org/stable/c/a341c091ca0bfae377747b1b59a3bd8ebe18a937"},{"url":"https://git.kernel.org/stable/c/6aea62e433fe1b586202a5fee8b5807ce635e1d7"}],"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 - fib6_rule_suppress() runs on every IPv6 route lookup via fib6_rule_lookup(), including ip6_route_input() for received packets and icmp6/icmpv6 redirect handlers; WireGuard/VPN servers commonly deploy suppress_prefixlength rules (wg-quick), so remote IPv6 traffic to those hosts reaches the bug.\nAC:L - Once suppress_prefixlength IPv6 policy routing rules exist, any matching packet deterministically triggers fib6_rule_suppress() to release the route while leaving a stale res->rt6 pointer; no race or uncontrollable memory layout is required.\nPR:N - Remote exploitation needs only the ability to send IPv6 packets through a host whose operator already configured suppress rules (e.g., wg-quick); CAP_NET_ADMIN is an admin deployment prerequisite, not attacker privilege on the target.\nUI:N - No victim action is required beyond normal delivery of attacker-generated IPv6 traffic (or ICMPv6 redirect) to a host performing policy-route lookup.\nS:U - The stale rt6_info/dst_entry UAF corrupts kernel heap memory within the same host security boundary; it is not a VM escape or cross-authority sandbox break.\nC:H - Returning a released rt6_info leaves a dangling dst_entry in ip6_dst_cache; subsequent reads through ip6_dst_idev(), dst metrics, or error paths are classic slab UAF with attacker-influencable heap reuse via sustained IPv6 traffic.\nI:H - Double-free/imbalanced rcuref put and post-free use of rt6_info fields give heap corruption primitives; UAF on dst/route cache objects is routinely leveraged for kernel write and control-flow hijack.\nA:H - Commit explicitly reports rcuref_put_slowpath() WARN from dst_release() on the freed route; UAF and refcount corruption can oops/panic the kernel, fully denying availability."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-25T05:40:07.594Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.84","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.7","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.6.151"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.12.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.18.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"7.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.164"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-74581","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T19:01:10.675016Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T19:05:58.061Z"}}]}}}