{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31504","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-03-09T15:48:24.105Z","datePublished":"2026-04-22T13:54:23.862Z","dateUpdated":"2026-05-11T22:10:01.711Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-05-11T22:10:01.711Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: fix fanout UAF in packet_release() via NETDEV_UP race\n\n`packet_release()` has a race window where `NETDEV_UP` can re-register a\nsocket into a fanout group's `arr[]` array. The re-registration is not\ncleaned up by `fanout_release()`, leaving a dangling pointer in the fanout\narray.\n`packet_release()` does NOT zero `po->num` in its `bind_lock` section.\nAfter releasing `bind_lock`, `po->num` is still non-zero and `po->ifindex`\nstill matches the bound device. A concurrent `packet_notifier(NETDEV_UP)`\nthat already found the socket in `sklist` can re-register the hook.\nFor fanout sockets, this re-registration calls `__fanout_link(sk, po)`\nwhich adds the socket back into `f->arr[]` and increments `f->num_members`,\nbut does NOT increment `f->sk_ref`.\n\nThe fix sets `po->num` to zero in `packet_release` while `bind_lock` is\nheld to prevent NETDEV_UP from linking, preventing the race window.\n\nThis bug was found following an additional audit with Claude Code based\non CVE-2025-38617."}],"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"}}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/packet/af_packet.c"],"versions":[{"version":"ce06b03e60fc19c680d1bf873e779bf11c2fc518","lessThan":"ee642b1962caa9aa231c01abbd58bc453ae6b66e","status":"affected","versionType":"git"},{"version":"ce06b03e60fc19c680d1bf873e779bf11c2fc518","lessThan":"42cfd7898eeed290c9fb73f732af1f7d6b0a703e","status":"affected","versionType":"git"},{"version":"ce06b03e60fc19c680d1bf873e779bf11c2fc518","lessThan":"1b4c03f8892d955385c202009af7485364731bb9","status":"affected","versionType":"git"},{"version":"ce06b03e60fc19c680d1bf873e779bf11c2fc518","lessThan":"654386baef228c2992dbf604c819e4c7c35fc71b","status":"affected","versionType":"git"},{"version":"ce06b03e60fc19c680d1bf873e779bf11c2fc518","lessThan":"75fe6db23705a1d55160081f7b37db9665b1880b","status":"affected","versionType":"git"},{"version":"ce06b03e60fc19c680d1bf873e779bf11c2fc518","lessThan":"d0c7cdc15fdf8c4f91aca1928e52295d175b6ec6","status":"affected","versionType":"git"},{"version":"ce06b03e60fc19c680d1bf873e779bf11c2fc518","lessThan":"ceccbfc6de720ad633519a226715989cfb065af1","status":"affected","versionType":"git"},{"version":"ce06b03e60fc19c680d1bf873e779bf11c2fc518","lessThan":"42156f93d123436f2a27c468f18c966b7e5db796","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/packet/af_packet.c"],"versions":[{"version":"3.1","status":"affected"},{"version":"0","lessThan":"3.1","status":"unaffected","versionType":"semver"},{"version":"5.10.253","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.203","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.168","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.131","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.80","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.21","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"6.19.11","lessThanOrEqual":"6.19.*","status":"unaffected","versionType":"semver"},{"version":"7.0","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":"3.1","versionEndExcluding":"5.10.253"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"5.15.203"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.1.168"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.6.131"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.12.80"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.18.21"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.19.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"7.0"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/ee642b1962caa9aa231c01abbd58bc453ae6b66e"},{"url":"https://git.kernel.org/stable/c/42cfd7898eeed290c9fb73f732af1f7d6b0a703e"},{"url":"https://git.kernel.org/stable/c/1b4c03f8892d955385c202009af7485364731bb9"},{"url":"https://git.kernel.org/stable/c/654386baef228c2992dbf604c819e4c7c35fc71b"},{"url":"https://git.kernel.org/stable/c/75fe6db23705a1d55160081f7b37db9665b1880b"},{"url":"https://git.kernel.org/stable/c/d0c7cdc15fdf8c4f91aca1928e52295d175b6ec6"},{"url":"https://git.kernel.org/stable/c/ceccbfc6de720ad633519a226715989cfb065af1"},{"url":"https://git.kernel.org/stable/c/42156f93d123436f2a27c468f18c966b7e5db796"}],"title":"net: fix fanout UAF in packet_release() via NETDEV_UP race","x_generator":{"engine":"bippy-1.2.0"}}}}