{"id":"CVE-2026-43036","state":"PUBLISHED","title":"net: use skb_header_pointer() for TCPv4 GSO frag_off check","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: use skb_header_pointer() for TCPv4 GSO frag_off check\n\nSyzbot reported a KMSAN uninit-value warning in gso_features_check()\ncalled from netif_skb_features() [1].\n\ngso_features_check() reads iph->frag_off to decide whether to clear\nmangleid_features. Accessing the IPv4 header via ip_hdr()/inner_ip_hdr()\ncan rely on skb header offsets that are not always safe for direct\ndereference on packets injected from PF_PACKET paths.\n\nUse skb_header_pointer() for the TCPv4 frag_off check so the header read\nis robust whether data is already linear or needs copying.\n\n[1] https://syzkaller.appspot.com/bug?extid=1543a7d954d9c6d00407","publishedAt":"2026-05-01T14:15:34.640Z","updatedAt":"2026-10-30T12:24:49.808Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"362bacb37d88a178bfaefc4484623eae44425a70","versionType":"git"},{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"5057502630fbc8ce468ff617ff59af275960b537","versionType":"git"},{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"f7a6cd508e9e825a2c69fa9e13d41ee156852f25","versionType":"git"},{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"cc91202fc20a44aab4c206f12a2bfe05da936051","versionType":"git"},{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"d970341cfa5594614c7a6634886c7688b4f5cafd","versionType":"git"},{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/dev.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.7","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.81","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.22","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.12","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/core/dev.c"]}],"references":["https://git.kernel.org/stable/c/362bacb37d88a178bfaefc4484623eae44425a70","https://git.kernel.org/stable/c/5057502630fbc8ce468ff617ff59af275960b537","https://git.kernel.org/stable/c/f7a6cd508e9e825a2c69fa9e13d41ee156852f25","https://git.kernel.org/stable/c/cc91202fc20a44aab4c206f12a2bfe05da936051","https://git.kernel.org/stable/c/d970341cfa5594614c7a6634886c7688b4f5cafd","https://git.kernel.org/stable/c/ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0"],"weaknesses":[],"ingestedAt":"2026-10-30T12:42:04.495Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/43xxx/CVE-2026-43036.json","commit":"db8103c5921aac81d5d90efcf3745980dafabf49","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-43036","state":"PUBLISHED","datePublished":"2026-05-01T14:15:34.640Z","dateUpdated":"2026-10-30T12:24:49.808Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-01T14:12:55.977Z"},"containers":{"cna":{"title":"net: use skb_header_pointer() for TCPv4 GSO frag_off check","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: use skb_header_pointer() for TCPv4 GSO frag_off check\n\nSyzbot reported a KMSAN uninit-value warning in gso_features_check()\ncalled from netif_skb_features() [1].\n\ngso_features_check() reads iph->frag_off to decide whether to clear\nmangleid_features. Accessing the IPv4 header via ip_hdr()/inner_ip_hdr()\ncan rely on skb header offsets that are not always safe for direct\ndereference on packets injected from PF_PACKET paths.\n\nUse skb_header_pointer() for the TCPv4 frag_off check so the header read\nis robust whether data is already linear or needs copying.\n\n[1] https://syzkaller.appspot.com/bug?extid=1543a7d954d9c6d00407"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"362bacb37d88a178bfaefc4484623eae44425a70","versionType":"git"},{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"5057502630fbc8ce468ff617ff59af275960b537","versionType":"git"},{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"f7a6cd508e9e825a2c69fa9e13d41ee156852f25","versionType":"git"},{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"cc91202fc20a44aab4c206f12a2bfe05da936051","versionType":"git"},{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"d970341cfa5594614c7a6634886c7688b4f5cafd","versionType":"git"},{"version":"cbc53e08a793b073e79f42ca33f1f3568703540d","status":"affected","lessThan":"ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/dev.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.7","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.81","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.22","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.12","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/core/dev.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/362bacb37d88a178bfaefc4484623eae44425a70"},{"url":"https://git.kernel.org/stable/c/5057502630fbc8ce468ff617ff59af275960b537"},{"url":"https://git.kernel.org/stable/c/f7a6cd508e9e825a2c69fa9e13d41ee156852f25"},{"url":"https://git.kernel.org/stable/c/cc91202fc20a44aab4c206f12a2bfe05da936051"},{"url":"https://git.kernel.org/stable/c/d970341cfa5594614c7a6634886c7688b4f5cafd"},{"url":"https://git.kernel.org/stable/c/ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:24:49.808Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.7","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.7","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.7","versionEndExcluding":"6.12.81"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.7","versionEndExcluding":"6.18.22"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.7","versionEndExcluding":"6.19.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.7","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}