{"id":"CVE-2026-31684","state":"PUBLISHED","title":"net: sched: act_csum: validate nested VLAN headers","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: act_csum: validate nested VLAN headers\n\ntcf_csum_act() walks nested VLAN headers directly from skb->data when an\nskb still carries in-payload VLAN tags. The current code reads\nvlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without\nfirst ensuring that the full VLAN header is present in the linear area.\n\nIf only part of an inner VLAN header is linearized, accessing\nh_vlan_encapsulated_proto reads past the linear area, and the following\nskb_pull(VLAN_HLEN) may violate skb invariants.\n\nFix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and\npulling each nested VLAN header. If the header still is not fully\navailable, drop the packet through the existing error path.","publishedAt":"2026-04-25T08:47:01.555Z","updatedAt":"2026-06-01T16:13:24.352Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"0410c619e86551677fb79887a38eccad3f5a0725","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"886469b6455611a511aa6013e957e15e50577513","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"46c07ad50fa2f4ba7663ee1b72b75ad7ad45cf09","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"eb3765b90eb8f2a3d6310a80c14a9e57ec4267a2","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"a69738efea0996d05a3c7d2178551b891744df1b","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"ec4930979b3f7bbeb7af5744599fc6603a4dba62","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"3d165d975305cf76ff0b10a3c798fb31e5f5f9a5","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"c842743d073bdd683606cb414eb0ca84465dd834","versionType":"git"},{"version":"3764bfae5056e95617b6ee074129297e11710886","status":"affected","versionType":"git"},{"version":"4.19.99","status":"affected","lessThan":"4.20","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/act_csum.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.1","versionType":"semver"},{"version":"5.10.258","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.209","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.136","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.83","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.24","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.14","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/act_csum.c"]}],"references":["https://git.kernel.org/stable/c/0410c619e86551677fb79887a38eccad3f5a0725","https://git.kernel.org/stable/c/886469b6455611a511aa6013e957e15e50577513","https://git.kernel.org/stable/c/46c07ad50fa2f4ba7663ee1b72b75ad7ad45cf09","https://git.kernel.org/stable/c/eb3765b90eb8f2a3d6310a80c14a9e57ec4267a2","https://git.kernel.org/stable/c/a69738efea0996d05a3c7d2178551b891744df1b","https://git.kernel.org/stable/c/ec4930979b3f7bbeb7af5744599fc6603a4dba62","https://git.kernel.org/stable/c/3d165d975305cf76ff0b10a3c798fb31e5f5f9a5","https://git.kernel.org/stable/c/c842743d073bdd683606cb414eb0ca84465dd834"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31684.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31684","state":"PUBLISHED","datePublished":"2026-04-25T08:47:01.555Z","dateUpdated":"2026-06-01T16:13:24.352Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.130Z"},"containers":{"cna":{"title":"net: sched: act_csum: validate nested VLAN headers","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: act_csum: validate nested VLAN headers\n\ntcf_csum_act() walks nested VLAN headers directly from skb->data when an\nskb still carries in-payload VLAN tags. The current code reads\nvlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without\nfirst ensuring that the full VLAN header is present in the linear area.\n\nIf only part of an inner VLAN header is linearized, accessing\nh_vlan_encapsulated_proto reads past the linear area, and the following\nskb_pull(VLAN_HLEN) may violate skb invariants.\n\nFix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and\npulling each nested VLAN header. If the header still is not fully\navailable, drop the packet through the existing error path."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"0410c619e86551677fb79887a38eccad3f5a0725","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"886469b6455611a511aa6013e957e15e50577513","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"46c07ad50fa2f4ba7663ee1b72b75ad7ad45cf09","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"eb3765b90eb8f2a3d6310a80c14a9e57ec4267a2","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"a69738efea0996d05a3c7d2178551b891744df1b","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"ec4930979b3f7bbeb7af5744599fc6603a4dba62","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"3d165d975305cf76ff0b10a3c798fb31e5f5f9a5","versionType":"git"},{"version":"2ecba2d1e45b24620a7c3df9531895cf68d5dec6","status":"affected","lessThan":"c842743d073bdd683606cb414eb0ca84465dd834","versionType":"git"},{"version":"3764bfae5056e95617b6ee074129297e11710886","status":"affected","versionType":"git"},{"version":"4.19.99","status":"affected","lessThan":"4.20","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/act_csum.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.1","versionType":"semver"},{"version":"5.10.258","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.209","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.136","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.83","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.24","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.14","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/act_csum.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/0410c619e86551677fb79887a38eccad3f5a0725"},{"url":"https://git.kernel.org/stable/c/886469b6455611a511aa6013e957e15e50577513"},{"url":"https://git.kernel.org/stable/c/46c07ad50fa2f4ba7663ee1b72b75ad7ad45cf09"},{"url":"https://git.kernel.org/stable/c/eb3765b90eb8f2a3d6310a80c14a9e57ec4267a2"},{"url":"https://git.kernel.org/stable/c/a69738efea0996d05a3c7d2178551b891744df1b"},{"url":"https://git.kernel.org/stable/c/ec4930979b3f7bbeb7af5744599fc6603a4dba62"},{"url":"https://git.kernel.org/stable/c/3d165d975305cf76ff0b10a3c798fb31e5f5f9a5"},{"url":"https://git.kernel.org/stable/c/c842743d073bdd683606cb414eb0ca84465dd834"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-06-01T16:13:24.352Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"5.10.258"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"5.15.209"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"6.1.175"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"6.6.136"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"6.12.83"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"6.18.24"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"6.19.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"7.0"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.19.99"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}