# net: tap: fix wrong transport_header when sending VLAN-tagged frame

CVE record · `CVE-2026-80905`

- **Identifiers:** `CVE-2026-80905`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 4 Sept 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 4 Sept 2026, 17:19 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `8c76e77f9069f10505c08e02646c3ee11ad79038 to before a8f49e83e4447b885376e6a937d62df883cc8824` (git)
  - affected: `8c76e77f9069f10505c08e02646c3ee11ad79038 to before c0376820922d255ae1d103c32345a6ec4c3266f7` (git)
  - affected: `8c76e77f9069f10505c08e02646c3ee11ad79038 to before f1d297cad5c1eacd9fadfd0346ad97405ffbf97c` (git)
  - affected: `8c76e77f9069f10505c08e02646c3ee11ad79038 to before 5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b` (git)
  - affected: `8c76e77f9069f10505c08e02646c3ee11ad79038 to before 88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3` (git)
  - affected: `8c76e77f9069f10505c08e02646c3ee11ad79038 to before cbb35cbe8db268fefe34c23df15348cf99025298` (git)
  - affected: `3cae5ef1f37a475faf7c40bc6a3c170779f3e0b1` (git)
  - affected: `4.20.1 to before 4.21` (semver)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.0`
  - unaffected: `before 5.0` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.114 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.46 to 6.18.*, inclusive` (semver)
  - unaffected: `7.1.10 to 7.1.*, inclusive` (semver)
  - unaffected: `7.2 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> The Linux kernel tap driver can set a wrong transport header for VLAN-tagged frames, leaving it uninitialized. Affected versions start at 5.0; the source gives few details on attacker requirements or impact. Upgrade to Linux 6.1.191 or later, 6.6.160 or later, 6.12.114 or later, or 6.18.46 or later, depending on your series.

Written 12 Nov 2026.

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

No source has published a CVSS score for this record yet.

- **CISA KEV:** Not listed.
- **EPSS:** 0.0020, the 10th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 4 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-80905](https://www.cve.org/CVERecord?id=CVE-2026-80905)
- [NVD: CVE-2026-80905](https://nvd.nist.gov/vuln/detail/CVE-2026-80905)

### References from the CNA

- <https://git.kernel.org/stable/c/a8f49e83e4447b885376e6a937d62df883cc8824>
- <https://git.kernel.org/stable/c/c0376820922d255ae1d103c32345a6ec4c3266f7>
- <https://git.kernel.org/stable/c/f1d297cad5c1eacd9fadfd0346ad97405ffbf97c>
- <https://git.kernel.org/stable/c/5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b>
- <https://git.kernel.org/stable/c/88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3>
- <https://git.kernel.org/stable/c/cbb35cbe8db268fefe34c23df15348cf99025298>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-80905>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-80905/>. Everything for agents: <https://agentprime.io/llms.txt>.