{
  "cveId": "CVE-2026-80905",
  "url": "https://patchblox.com/security/cve/CVE-2026-80905",
  "summary": "CVE-2026-80905 is fixed in 20 products on 1 platform, first by DEBIAN-CVE-2026-80905, released September 5, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "net: tap: fix wrong transport_header when sending VLAN-tagged frame",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  net: tap: fix wrong transport_header when sending VLAN-tagged frame  In tap_get_user_xdp(), when processing a VLAN-tagged frame (e.g. ETH_P_8021Q), skb_set_network_header() is called first to advance network_header past the VLAN tag to the inner protocol header. skb_probe_transport_header() is then called with skb-\u003Eprotocol still set to ETH_P_8021Q, while nhoff (derived from skb_network_offset()) already points past the VLAN tag to the inner protocol header.  In __skb_flow_dissect(), proto is initialized to ETH_P_8021Q and nhoff points past the VLAN tag. When the dissector hits case ETH_P_8021Q, it reads a struct vlan_hdr at the current nhoff via __skb_header_pointer(), but that offset contains the inner protocol header (e.g. an IP header). The bytes are misinterpreted as a VLAN header, yielding a garbage encapsulated EtherType that matches no known protocol. The dissector returns false, so skb_probe_transport_header() never calls skb_set_transport_header(), leaving transport_header at its uninitialized sentinel value (~0U).  Move skb_set_network_header() to after skb_probe_transport_header(). At the time skb_probe_transport_header() is called, network_header still points to the VLAN header (offset ETH_HLEN), so nhoff is correct and the flow dissector can parse the VLAN header, extract the inner EtherType, and advance nhoff to the inner protocol header, allowing transport_header to be set correctly.",
  "published": "2026-09-04T18:18:00Z",
  "severity": "Moderate",
  "cvss": 5.5,
  "epss": 0.00204,
  "epssPercentile": 0.10405,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-80905",
  "fixes": [
    {
      "platform": "linux",
      "product": "bpftool6.18",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.48-107.148.amzn2023",
      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "bpftool6.18-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.48-107.148.amzn2023",
      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "kernel-livepatch-6.18.48-107.148",
      "release": "amzn 2023",
      "fixedVersion": "1:1.0-0.amzn2023",
      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
    {
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      "product": "kernel6.18",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.48-107.148.amzn2023",
      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
    {
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      "product": "kernel6.18-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.48-107.148.amzn2023",
      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "kernel6.18-debuginfo-common-aarch64",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.48-107.148.amzn2023",
      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
    {
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      "product": "kernel6.18-debuginfo-common-x86_64",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.48-107.148.amzn2023",
      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
    {
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      "product": "kernel6.18-devel",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.48-107.148.amzn2023",
      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
    {
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      "product": "kernel6.18-headers",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.48-107.148.amzn2023",
      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
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      "product": "kernel6.18-modules-extra",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.48-107.148.amzn2023",
      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
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      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
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      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
    {
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      "release": "amzn 2023",
      "fixedVersion": "1:6.18.48-107.148.amzn2023",
      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
    {
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      "fix": "ALAS2023-2026-3139",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3139",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.115-2",
      "fix": "DEBIAN-CVE-2026-80905",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-80905",
      "released": "2026-09-05T01:57:10Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.1.10-1",
      "fix": "DEBIAN-CVE-2026-80905",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-80905",
      "released": "2026-09-05T01:57:10Z"
    },
    {
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      "release": "amzn 2023",
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      "fix": "ALAS2023-2026-3139",
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      "released": "2026-09-28T09:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}