---
id: CVE-2026-80905
title: >-
  kernel: net: tap: fix wrong transport_header when sending VLAN-tagged frame
  (CVE-2026-80905)
summary: >-
  A flaw was found in the kernel. When processing VLAN-tagged frames, the
  network header is incorrectly advanced past the VLAN tag before the transport
  header is probed. This misinterprets the inner protocol header as a VLAN
  header, resultin…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe: CWE-20
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 8
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-04'
updated: '2026-10-25'
sourceUpdated: '2026-10-25T21:47:09+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80905.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80905.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-80905'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2528795'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-80905'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80905'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80905.mbox
  - url: 'https://kernelcve.org/list/?q=CVE-2026-80905'
  - url: 'https://git.kernel.org/stable/c/c0376820922d255ae1d103c32345a6ec4c3266f7'
  - url: 'https://git.kernel.org/stable/c/f1d297cad5c1eacd9fadfd0346ad97405ffbf97c'
  - url: 'https://git.kernel.org/stable/c/5ffaa5d7f56ab24a8e23cf131eadfef31a3bbc4b'
  - url: 'https://git.kernel.org/stable/c/88b79ac89ecc04d7f2613f7e1c0b46f0c4ddb2f3'
  - url: 'https://git.kernel.org/stable/c/cbb35cbe8db268fefe34c23df15348cf99025298'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00209
epssPercentile: 0.10937
ingestedAt: '2026-10-21T12:48:53.748Z'
---

## Overview

A flaw was found in the kernel. When processing VLAN-tagged frames, the network header is incorrectly advanced past the VLAN tag before the transport header is probed. This misinterprets the inner protocol header as a VLAN header, resulting in an uninitialized transport header. This issue can lead to incorrect packet dissection and potentially affect network functionality.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-25 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80905.json)

**kernel: net: tap: fix wrong transport_header when sending VLAN-tagged frame** — rated Moderate by Red Hat. Released 2026-09-04, updated 2026-10-25.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

Not affected:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7

## Remediation

Fix deferred

Workarounds / mitigations:

- Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.