{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98377","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-25T10:25:14.345Z","datePublished":"2026-10-09T07:34:17.832Z","dateUpdated":"2026-10-09T07:34:17.832Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-10-09T07:34:17.832Z"},"descriptions":[{"lang":"en","value":"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."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/if_vlan.h"],"versions":[{"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"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/if_vlan.h"],"versions":[{"version":"2.6.12","status":"affected"},{"version":"0","lessThan":"2.6.12","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-rc5","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":"2.6.12","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.3-rc5"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/40a5cc4b7251c74f3341332a226d02200e96bccf"},{"url":"https://git.kernel.org/stable/c/f42562dd027dc4ed103fae17b2206e73ea1963c4"},{"url":"https://git.kernel.org/stable/c/59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdc"},{"url":"https://git.kernel.org/stable/c/ab888242fce4f16f6c4d4c6ec53939ad36aa3b3a"}],"title":"vlan: require the MAC header to be present in __vlan_insert_inner_tag()","x_generator":{"engine":"bippy-1.2.0"}}}}