{"api_version":"1","generated_at":"2026-10-27T20:21:02+00:00","cve":"CVE-2026-98955","urls":{"html":"https://cve.report/CVE-2026-98955","api":"https://cve.report/api/cve/CVE-2026-98955.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98955","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98955"},"summary":{"title":"flow_dissector: avoid u16 truncation of skb->len when computing thoff","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-23 13:17:16","updated_at":"2026-10-23 13:17:16"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/d9e08836d06c84abb18470c94b12b131eaccdc7d","name":"https://git.kernel.org/stable/c/d9e08836d06c84abb18470c94b12b131eaccdc7d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/99bda1ecbd56905f8bd934b9cdccd3bd251192b1","name":"https://git.kernel.org/stable/c/99bda1ecbd56905f8bd934b9cdccd3bd251192b1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/52efce4755a4b8b82039caa773645ffc80b25362","name":"https://git.kernel.org/stable/c/52efce4755a4b8b82039caa773645ffc80b25362","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/50d0cd575cab763f833d6ac6eb6550b23a0b3dae","name":"https://git.kernel.org/stable/c/50d0cd575cab763f833d6ac6eb6550b23a0b3dae","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9993e6a0ac1b5b3101ffba702cacb9f42b9909d8","name":"https://git.kernel.org/stable/c/9993e6a0ac1b5b3101ffba702cacb9f42b9909d8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98955","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98955","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d0c081b49137cd3200f2023c0875723be66e7ce5 d9e08836d06c84abb18470c94b12b131eaccdc7d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d0c081b49137cd3200f2023c0875723be66e7ce5 50d0cd575cab763f833d6ac6eb6550b23a0b3dae git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d0c081b49137cd3200f2023c0875723be66e7ce5 9993e6a0ac1b5b3101ffba702cacb9f42b9909d8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d0c081b49137cd3200f2023c0875723be66e7ce5 52efce4755a4b8b82039caa773645ffc80b25362 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d0c081b49137cd3200f2023c0875723be66e7ce5 99bda1ecbd56905f8bd934b9cdccd3bd251192b1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d35cd5e279881ec36ff8cd82a2d9caebc0cce3fc git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected eecfa2eeefe3caef4c8d6b2284f6066c76ab26a1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 80f327285cab6ab8e10c3ea03278add5dd99fb02 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.4.114 4.5 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.9.79 4.10 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.14.16 4.15 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.15","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.15 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.160 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.113 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.57 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.11 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/core/flow_dissector.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"d9e08836d06c84abb18470c94b12b131eaccdc7d","status":"affected","version":"d0c081b49137cd3200f2023c0875723be66e7ce5","versionType":"git"},{"lessThan":"50d0cd575cab763f833d6ac6eb6550b23a0b3dae","status":"affected","version":"d0c081b49137cd3200f2023c0875723be66e7ce5","versionType":"git"},{"lessThan":"9993e6a0ac1b5b3101ffba702cacb9f42b9909d8","status":"affected","version":"d0c081b49137cd3200f2023c0875723be66e7ce5","versionType":"git"},{"lessThan":"52efce4755a4b8b82039caa773645ffc80b25362","status":"affected","version":"d0c081b49137cd3200f2023c0875723be66e7ce5","versionType":"git"},{"lessThan":"99bda1ecbd56905f8bd934b9cdccd3bd251192b1","status":"affected","version":"d0c081b49137cd3200f2023c0875723be66e7ce5","versionType":"git"},{"status":"affected","version":"d35cd5e279881ec36ff8cd82a2d9caebc0cce3fc","versionType":"git"},{"status":"affected","version":"eecfa2eeefe3caef4c8d6b2284f6066c76ab26a1","versionType":"git"},{"status":"affected","version":"80f327285cab6ab8e10c3ea03278add5dd99fb02","versionType":"git"},{"lessThan":"4.5","status":"affected","version":"4.4.114","versionType":"semver"},{"lessThan":"4.10","status":"affected","version":"4.9.79","versionType":"semver"},{"lessThan":"4.15","status":"affected","version":"4.14.16","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/core/flow_dissector.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.15"},{"lessThan":"4.15","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.160","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.113","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.57","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.11","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.160","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.113","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.57","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.11","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4.114","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9.79","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14.16","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"providerMetadata":{"dateUpdated":"2026-10-23T12:19:15.287Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/d9e08836d06c84abb18470c94b12b131eaccdc7d"},{"url":"https://git.kernel.org/stable/c/50d0cd575cab763f833d6ac6eb6550b23a0b3dae"},{"url":"https://git.kernel.org/stable/c/9993e6a0ac1b5b3101ffba702cacb9f42b9909d8"},{"url":"https://git.kernel.org/stable/c/52efce4755a4b8b82039caa773645ffc80b25362"},{"url":"https://git.kernel.org/stable/c/99bda1ecbd56905f8bd934b9cdccd3bd251192b1"}],"title":"flow_dissector: avoid u16 truncation of skb->len when computing thoff","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98955","datePublished":"2026-10-23T12:19:15.287Z","dateReserved":"2026-09-25T10:25:14.382Z","dateUpdated":"2026-10-23T12:19:15.287Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-23 13:17:16","lastModifiedDate":"2026-10-23 13:17:16","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98955","Ordinal":"1","Title":"flow_dissector: avoid u16 truncation of skb->len when computing ","CVE":"CVE-2026-98955","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98955","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"flow_dissector: avoid u16 truncation of skb->len when computing "}]}}}