{"schema":"threatline.record/2","record":{"id":"CVE-2026-98955","aliases":[],"summary":"flow_dissector: avoid u16 truncation of skb->len when computing thoff","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nflow_dissector: avoid u16 truncation of skb->len when computing thoff\n\n__skb_flow_dissect() computes key_control->thoff using:\n\n  key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen);\n\nmin_t(u16, ...) casts both arguments to u16 before comparing them.\nWhenever skb->len (or hlen) modulo 65536 is smaller than nhoff, the\ntruncated length wins and thoff is set to a bogus small value, even\nwhen the dissection succeeded. For example, an IPv4/TCP frame with\nskb->len == 65540 and nhoff == 34 gets thoff == 4, so callers such as\nskb_probe_transport_header() point the transport header inside the\nEthernet header.\n\nSuch skbs are not exotic:\n- At the time of commit d0c081b49137 (\"flow_dissector: properly cap\n  thoff field\"), AF_PACKET with PACKET_VNET_HDR could already build GSO\n  skbs larger than 64KB (MTU checks are skipped for GSO, and\n  alloc_skb_with_frags() accepted up to MAX_SKB_FRAGS (17) order-0\n  pages on top of the linear part).\n- BIG TCP now makes skbs larger than 64KB common.\n- The following patch makes tun_get_user() dissect IFF_TAP frames\n  before eth_type_trans() pulls the Ethernet header, so a GSO frame\n  carrying a 65522..65535 byte L3 packet will be dissected with\n  skb->len in [65536, 65549].\n\nCompare as u32 instead. If the resulting offset cannot be represented\nin the u16 key_control->thoff, cap it to U16_MAX and report the\ndissection as failed rather than silently returning a wrong transport\noffset. thoff is still set on failure, as some callers (such as\neth_get_headlen()) use it regardless of the return value.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98955","source_modified_at":"2026-10-23T12:19:15.287Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Linux","vendor":"Linux","versions":[{"version":"d0c081b49137cd3200f2023c0875723be66e7ce5","lessThan":"d9e08836d06c84abb18470c94b12b131eaccdc7d","status":"affected","versionType":"git"},{"version":"d0c081b49137cd3200f2023c0875723be66e7ce5","lessThan":"50d0cd575cab763f833d6ac6eb6550b23a0b3dae","status":"affected","versionType":"git"},{"version":"d0c081b49137cd3200f2023c0875723be66e7ce5","lessThan":"9993e6a0ac1b5b3101ffba702cacb9f42b9909d8","status":"affected","versionType":"git"},{"version":"d0c081b49137cd3200f2023c0875723be66e7ce5","lessThan":"52efce4755a4b8b82039caa773645ffc80b25362","status":"affected","versionType":"git"},{"version":"d0c081b49137cd3200f2023c0875723be66e7ce5","lessThan":"99bda1ecbd56905f8bd934b9cdccd3bd251192b1","status":"affected","versionType":"git"},{"version":"d35cd5e279881ec36ff8cd82a2d9caebc0cce3fc","status":"affected","versionType":"git"},{"version":"eecfa2eeefe3caef4c8d6b2284f6066c76ab26a1","status":"affected","versionType":"git"},{"version":"80f327285cab6ab8e10c3ea03278add5dd99fb02","status":"affected","versionType":"git"},{"version":"4.4.114","lessThan":"4.5","status":"affected","versionType":"semver"},{"version":"4.9.79","lessThan":"4.10","status":"affected","versionType":"semver"},{"version":"4.14.16","lessThan":"4.15","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98955","source_modified_at":"2026-10-23T12:19:15.287Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Linux","vendor":"Linux","versions":[{"version":"4.15","status":"affected"},{"version":"0","lessThan":"4.15","status":"unaffected","versionType":"semver"},{"version":"6.6.160","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.113","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.57","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.11","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98955","source_modified_at":"2026-10-23T12:19:15.287Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"50d0cd575cab763f833d6ac6eb6550b23a0b3dae","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98955","source_modified_at":"2026-10-23T12:19:15.287Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"9993e6a0ac1b5b3101ffba702cacb9f42b9909d8","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98955","source_modified_at":"2026-10-23T12:19:15.287Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"52efce4755a4b8b82039caa773645ffc80b25362","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98955","source_modified_at":"2026-10-23T12:19:15.287Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"99bda1ecbd56905f8bd934b9cdccd3bd251192b1","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98955","source_modified_at":"2026-10-23T12:19:15.287Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"4.5","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98955","source_modified_at":"2026-10-23T12:19:15.287Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"4.10","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98955","source_modified_at":"2026-10-23T12:19:15.287Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"4.15","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":null,"percentile":null,"score_date":null},"published_at":"2026-10-23T12:19:15.287Z","modified_at":"2026-10-23T12:19:15.287Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98955","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23T12:19:15.287Z"}],"sources":["CVE List"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/d9e08836d06c84abb18470c94b12b131eaccdc7d"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/50d0cd575cab763f833d6ac6eb6550b23a0b3dae"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/9993e6a0ac1b5b3101ffba702cacb9f42b9909d8"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/52efce4755a4b8b82039caa773645ffc80b25362"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/99bda1ecbd56905f8bd934b9cdccd3bd251192b1"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-23T12:19:15.287Z","content_hash":"f35c201755c4a9bcb187e0558559ecdcb94602e903e2ab127faab6d055250ce4"}}