CVE-2026-80905net: tap: fix wrong transport_header when sending VLAN-tagged frame
- —Not scoredno CVSS score yet
- 0.20%Exploitation in 30 daysEPSS · top 90% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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->protocol 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.
Timeline
ID reserved
By Linux
- 9 days later
· 9 days later
Published
- 56 days later
· 56 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.20% · top 90% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 8c76e77f9069f10505c08e02646c3ee11ad79038 – < a8f49e83e4447b885376e6a937d62df883cc8824
- affected 8c76e77f9069f10505c08e02646c3ee11ad79038 – < c0376820922d255ae1d103c32345a6ec4c3266f7
- affected 8c76e77f9069f10505c08e02646c3ee11ad79038 – < f1d297cad5c1eacd9fadfd0346ad97405ffbf97c
- affected 8c76e77f9069f10505c08e02646c3ee11ad79038 – < 5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b
- affected 8c76e77f9069f10505c08e02646c3ee11ad79038 – < 88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3
- affected 8c76e77f9069f10505c08e02646c3ee11ad79038 – < cbb35cbe8db268fefe34c23df15348cf99025298
- affected 3cae5ef1f37a475faf7c40bc6a3c170779f3e0b1
- affected 4.20.1 – < 4.21
- affected 5.0
- unaffected < 5.0
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.114 – ≤ 6.12.*
- unaffected 6.18.46 – ≤ 6.18.*
- unaffected 7.1.10 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References6
- https://git.kernel.org/stable/c/a8f49e83e4447b885376e6a937d62df883cc8824 (opens in a new tab)
- https://git.kernel.org/stable/c/c0376820922d255ae1d103c32345a6ec4c3266f7 (opens in a new tab)
- https://git.kernel.org/stable/c/f1d297cad5c1eacd9fadfd0346ad97405ffbf97c (opens in a new tab)
- https://git.kernel.org/stable/c/5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b (opens in a new tab)
- https://git.kernel.org/stable/c/88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3 (opens in a new tab)
- https://git.kernel.org/stable/c/cbb35cbe8db268fefe34c23df15348cf99025298 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-71664 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2026-80905)Record last updated .