{"schema":"threatline.record/2","record":{"id":"CVE-2026-98377","aliases":[],"summary":"vlan: require the MAC header to be present in __vlan_insert_inner_tag()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nvlan: require the MAC header to be present in __vlan_insert_inner_tag()\n\n__vlan_insert_inner_tag() only guarantees head room via skb_cow_head(),\nnever that mac_len bytes of MAC header are present.  Its ETH_HLEN\nwrappers - __vlan_insert_tag() under skb_vlan_push(), and\nvlan_insert_tag() under validate_xmit_vlan() on the generic transmit\npath - therefore rewrite the first 16 bytes at skb->data: a 12-byte\nmemmove plus two 2-byte stores at +12 and +14.  No caller supplies the\nbound, while the pop helpers use skb_ensure_writable()/pskb_may_pull().\n\nAn IFF_TUN device has hard_header_len == 0, so packet_snd() accepts a\none-byte AF_PACKET/SOCK_RAW frame.  The first vlan push only sets a\nhwaccel tag; the next - clsact \"action vlan push\" or\nbpf_skb_vlan_push() - enters the helper with skb->len still 1.  The\nhead comes from skbuff_small_head without __GFP_ZERO, so each push\ndrags bytes from beyond skb->tail into the frame.  After three the\none-byte send leaves as 13 bytes carrying 11 bytes of uninitialised\nslab:\n\n  0000: 5a b3 62 12 80 88 ff ff 00 b3 62 12 81\n           `------------------------------'\n  only 0x5a was sent; the rest is slab, here the top 56 bits of a\n  linear-map address\n\nRequire the MAC header the helper rewrites to be present, so such a\nframe is dropped rather than transmitted.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98377","source_modified_at":"2026-10-21T12:55:00.318Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"3d531429524df2c7116579306640283fea68bcf0","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"40a5cc4b7251c74f3341332a226d02200e96bccf","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"f42562dd027dc4ed103fae17b2206e73ea1963c4","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdc","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"ab888242fce4f16f6c4d4c6ec53939ad36aa3b3a","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98377","source_modified_at":"2026-10-21T12:55:00.318Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","lessThan":"2.6.12","status":"unaffected","versionType":"semver"},{"version":"6.6.160","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.55","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.9","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-2026-98377","source_modified_at":"2026-10-21T12:55:00.318Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"3d531429524df2c7116579306640283fea68bcf0","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98377","source_modified_at":"2026-10-21T12:55:00.318Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"40a5cc4b7251c74f3341332a226d02200e96bccf","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98377","source_modified_at":"2026-10-21T12:55:00.318Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdc","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00156,"percentile":0.044,"score_date":"2026-10-23"},"published_at":"2026-10-09T07:34:17.832Z","modified_at":"2026-10-21T12:55:00.318Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98377","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-21T12:55:00.318Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98377","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/3d531429524df2c7116579306640283fea68bcf0"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/40a5cc4b7251c74f3341332a226d02200e96bccf"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/f42562dd027dc4ed103fae17b2206e73ea1963c4"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdc"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/ab888242fce4f16f6c4d4c6ec53939ad36aa3b3a"}],"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":"2026-10-21T12:55:00.318Z","content_hash":"d9cfcdc61d3dad6665dd93c885190837b36421b7defde3c751894670abcedac5"}}