{"api_version":"1","generated_at":"2026-09-13T06:11:19+00:00","cve":"CVE-2026-80905","urls":{"html":"https://cve.report/CVE-2026-80905","api":"https://cve.report/api/cve/CVE-2026-80905.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80905","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80905"},"summary":{"title":"net: tap: fix wrong transport_header when sending VLAN-tagged frame","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-04 18:18:00","updated_at":"2026-09-04 18:18:00"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b","name":"https://git.kernel.org/stable/c/5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3","name":"https://git.kernel.org/stable/c/88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/cbb35cbe8db268fefe34c23df15348cf99025298","name":"https://git.kernel.org/stable/c/cbb35cbe8db268fefe34c23df15348cf99025298","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80905","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80905","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8c76e77f9069f10505c08e02646c3ee11ad79038 5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8c76e77f9069f10505c08e02646c3ee11ad79038 88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8c76e77f9069f10505c08e02646c3ee11ad79038 cbb35cbe8db268fefe34c23df15348cf99025298 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3cae5ef1f37a475faf7c40bc6a3c170779f3e0b1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.20.1 4.21 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.0","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.0 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.46 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.10 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"80905","cve":"CVE-2026-80905","epss":"0.001550000","percentile":"0.049000000","score_date":"2026-09-07","updated_at":"2026-09-08 00:05:26"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/net/tap.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b","status":"affected","version":"8c76e77f9069f10505c08e02646c3ee11ad79038","versionType":"git"},{"lessThan":"88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3","status":"affected","version":"8c76e77f9069f10505c08e02646c3ee11ad79038","versionType":"git"},{"lessThan":"cbb35cbe8db268fefe34c23df15348cf99025298","status":"affected","version":"8c76e77f9069f10505c08e02646c3ee11ad79038","versionType":"git"},{"status":"affected","version":"3cae5ef1f37a475faf7c40bc6a3c170779f3e0b1","versionType":"git"},{"lessThan":"4.21","status":"affected","version":"4.20.1","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/net/tap.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.0"},{"lessThan":"5.0","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.46","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.10","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.46","versionStartIncluding":"5.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.10","versionStartIncluding":"5.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"5.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20.1","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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."}],"providerMetadata":{"dateUpdated":"2026-09-04T17:19:15.289Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"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"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80905","datePublished":"2026-09-04T17:19:15.289Z","dateReserved":"2026-08-26T14:34:25.800Z","dateUpdated":"2026-09-04T17:19:15.289Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-04 18:18:00","lastModifiedDate":"2026-09-04 18:18:00","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80905","Ordinal":"1","Title":"net: tap: fix wrong transport_header when sending VLAN-tagged fr","CVE":"CVE-2026-80905","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80905","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"net: tap: fix wrong transport_header when sending VLAN-tagged fr"}]}}}