{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98955", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.382Z", "datePublished": "2026-10-23T12:19:15.287Z", "dateUpdated": "2026-10-23T12:19:15.287Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-23T12:19:15.287Z" }, "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." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/flow_dissector.c" ], "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" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/flow_dissector.c" ], "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" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.12.113" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.18.57" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "7.2.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "7.3" }, { "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" } ] } ] } ], "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" } } } }