{"id":"CVE-2026-98950","state":"PUBLISHED","title":"flow_dissector: avoid u16 truncation of hlen in bpf_flow_dissect()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nflow_dissector: avoid u16 truncation of hlen in bpf_flow_dissect()\n\nbpf_flow_dissect() sanitizes the offsets returned by the BPF program\nwith clamp_t(u16, ..., hlen).\n\nIf hlen is bigger than 65535, the upper bound is truncated before\nthe comparison. For instance, with hlen == 65536, both nhoff and\nthoff are forced to zero, even if the program returned sane values.\n\nThis is the same class of bug as the one fixed in commit 99bda1ecbd56\n(\"flow_dissector: avoid u16 truncation of skb->len when computing\nthoff\"). That fix does not cover the BPF path, because\n__skb_flow_dissect() returns early when a BPF flow dissector\nhandles the packet.\n\nstruct bpf_flow_keys stores nhoff and thoff as u16, so cap hlen\nto U16_MAX before clamping.\n\nFound by sashiko while reviewing the commit above.","publishedAt":"2026-10-23T12:19:09.890Z","updatedAt":"2026-10-30T12:40:29.247Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"46d21495f633e38d40857401504ee51c56ffed2a","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"6267f8304cbd9ec9f3f53bd227a733e07131492e","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"99c59062172620a0bac4ae8cf37c83bb78772cdd","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"c44c02c930c6583b235a1937c69ff716c4bb4514","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"3fb5ad2951a6df92c98f4f06cd70f20c50a2eb2a","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"cc18eb0e9941162c03f03f411ed7f6c339d91fa0","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"61b43a51a55929ec040bee3ea51af2121b956d05","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"f202578efc738b883cfa04889eb97328914265a7","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/flow_dissector.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.20","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.20","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","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":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.11","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/flow_dissector.c"]}],"references":["https://git.kernel.org/stable/c/46d21495f633e38d40857401504ee51c56ffed2a","https://git.kernel.org/stable/c/6267f8304cbd9ec9f3f53bd227a733e07131492e","https://git.kernel.org/stable/c/99c59062172620a0bac4ae8cf37c83bb78772cdd","https://git.kernel.org/stable/c/c44c02c930c6583b235a1937c69ff716c4bb4514","https://git.kernel.org/stable/c/3fb5ad2951a6df92c98f4f06cd70f20c50a2eb2a","https://git.kernel.org/stable/c/cc18eb0e9941162c03f03f411ed7f6c339d91fa0","https://git.kernel.org/stable/c/61b43a51a55929ec040bee3ea51af2121b956d05","https://git.kernel.org/stable/c/f202578efc738b883cfa04889eb97328914265a7"],"weaknesses":[],"ingestedAt":"2026-10-30T13:00:06.648Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98950.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98950","state":"PUBLISHED","datePublished":"2026-10-23T12:19:09.890Z","dateUpdated":"2026-10-30T12:40:29.247Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.382Z"},"containers":{"cna":{"title":"flow_dissector: avoid u16 truncation of hlen in bpf_flow_dissect()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nflow_dissector: avoid u16 truncation of hlen in bpf_flow_dissect()\n\nbpf_flow_dissect() sanitizes the offsets returned by the BPF program\nwith clamp_t(u16, ..., hlen).\n\nIf hlen is bigger than 65535, the upper bound is truncated before\nthe comparison. For instance, with hlen == 65536, both nhoff and\nthoff are forced to zero, even if the program returned sane values.\n\nThis is the same class of bug as the one fixed in commit 99bda1ecbd56\n(\"flow_dissector: avoid u16 truncation of skb->len when computing\nthoff\"). That fix does not cover the BPF path, because\n__skb_flow_dissect() returns early when a BPF flow dissector\nhandles the packet.\n\nstruct bpf_flow_keys stores nhoff and thoff as u16, so cap hlen\nto U16_MAX before clamping.\n\nFound by sashiko while reviewing the commit above."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"46d21495f633e38d40857401504ee51c56ffed2a","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"6267f8304cbd9ec9f3f53bd227a733e07131492e","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"99c59062172620a0bac4ae8cf37c83bb78772cdd","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"c44c02c930c6583b235a1937c69ff716c4bb4514","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"3fb5ad2951a6df92c98f4f06cd70f20c50a2eb2a","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"cc18eb0e9941162c03f03f411ed7f6c339d91fa0","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"61b43a51a55929ec040bee3ea51af2121b956d05","versionType":"git"},{"version":"d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9","status":"affected","lessThan":"f202578efc738b883cfa04889eb97328914265a7","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/flow_dissector.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.20","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.20","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","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":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.11","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/flow_dissector.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/46d21495f633e38d40857401504ee51c56ffed2a"},{"url":"https://git.kernel.org/stable/c/6267f8304cbd9ec9f3f53bd227a733e07131492e"},{"url":"https://git.kernel.org/stable/c/99c59062172620a0bac4ae8cf37c83bb78772cdd"},{"url":"https://git.kernel.org/stable/c/c44c02c930c6583b235a1937c69ff716c4bb4514"},{"url":"https://git.kernel.org/stable/c/3fb5ad2951a6df92c98f4f06cd70f20c50a2eb2a"},{"url":"https://git.kernel.org/stable/c/cc18eb0e9941162c03f03f411ed7f6c339d91fa0"},{"url":"https://git.kernel.org/stable/c/61b43a51a55929ec040bee3ea51af2121b956d05"},{"url":"https://git.kernel.org/stable/c/f202578efc738b883cfa04889eb97328914265a7"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:40:29.247Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"7.2.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}