{"id":"CVE-2026-98950","title":"flow_dissector: avoid u16 truncation of hlen in bpf_flow_dissect()","summary":"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\n…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < c44c02c930c6583b235a1937c69ff716c4bb4514","Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < 3fb5ad2951a6df92c98f4f06cd70f20c50a2eb2a","Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < cc18eb0e9941162c03f03f411ed7f6c339d91fa0","Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < 61b43a51a55929ec040bee3ea51af2121b956d05","Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < f202578efc738b883cfa04889eb97328914265a7","Linux 4.20"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T12:19:09.890Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98950","references":[{"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"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T13:24:55.557Z","slug":"CVE-2026-98950","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < c44c02c930c6583b235a1937c69ff716c4bb4514`\n- `Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < 3fb5ad2951a6df92c98f4f06cd70f20c50a2eb2a`\n- `Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < cc18eb0e9941162c03f03f411ed7f6c339d91fa0`\n- `Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < 61b43a51a55929ec040bee3ea51af2121b956d05`\n- `Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < f202578efc738b883cfa04889eb97328914265a7`\n- `Linux 4.20`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}