{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80905","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-26T14:34:25.800Z","datePublished":"2026-09-04T17:19:15.289Z","dateUpdated":"2026-09-04T17:19:15.289Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-04T17:19:15.289Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: tap: fix wrong transport_header when sending VLAN-tagged frame\n\nIn tap_get_user_xdp(), when processing a VLAN-tagged frame (e.g.\nETH_P_8021Q), skb_set_network_header() is called first to advance\nnetwork_header past the VLAN tag to the inner protocol header.\nskb_probe_transport_header() is then called with skb->protocol still\nset to ETH_P_8021Q, while nhoff (derived from skb_network_offset())\nalready points past the VLAN tag to the inner protocol header.\n\nIn __skb_flow_dissect(), proto is initialized to ETH_P_8021Q and nhoff\npoints past the VLAN tag. When the dissector hits case ETH_P_8021Q, it\nreads a struct vlan_hdr at the current nhoff via __skb_header_pointer(),\nbut that offset contains the inner protocol header (e.g. an IP header).\nThe bytes are misinterpreted as a VLAN header, yielding a garbage\nencapsulated EtherType that matches no known protocol. The dissector\nreturns false, so skb_probe_transport_header() never calls\nskb_set_transport_header(), leaving transport_header at its uninitialized\nsentinel value (~0U).\n\nMove skb_set_network_header() to after skb_probe_transport_header(). At\nthe time skb_probe_transport_header() is called, network_header still\npoints to the VLAN header (offset ETH_HLEN), so nhoff is correct and the\nflow dissector can parse the VLAN header, extract the inner EtherType,\nand advance nhoff to the inner protocol header, allowing transport_header\nto be set correctly."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/tap.c"],"versions":[{"version":"8c76e77f9069f10505c08e02646c3ee11ad79038","lessThan":"5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b","status":"affected","versionType":"git"},{"version":"8c76e77f9069f10505c08e02646c3ee11ad79038","lessThan":"88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3","status":"affected","versionType":"git"},{"version":"8c76e77f9069f10505c08e02646c3ee11ad79038","lessThan":"cbb35cbe8db268fefe34c23df15348cf99025298","status":"affected","versionType":"git"},{"version":"3cae5ef1f37a475faf7c40bc6a3c170779f3e0b1","status":"affected","versionType":"git"},{"version":"4.20.1","lessThan":"4.21","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/tap.c"],"versions":[{"version":"5.0","status":"affected"},{"version":"0","lessThan":"5.0","status":"unaffected","versionType":"semver"},{"version":"6.18.46","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.10","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","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":"5.0","versionEndExcluding":"6.18.46"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"7.1.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b"},{"url":"https://git.kernel.org/stable/c/88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3"},{"url":"https://git.kernel.org/stable/c/cbb35cbe8db268fefe34c23df15348cf99025298"}],"title":"net: tap: fix wrong transport_header when sending VLAN-tagged frame","x_generator":{"engine":"bippy-1.2.0"}}}}