---
id: CVE-2026-89562
title: 'ip6_gre: fix hardware header length for NBMA tunnels'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ip6_gre: fix hardware header length for NBMA tunnels

  ip6gre_tnl_link_config_route() accumulates the lower device's hardware
  header length into dev->hard_header_len whe…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee <
    cb1afd087aedc90e5274537e4fb9bf3f98e5afdb
  - >-
    Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee <
    7719f6e7ed2ffddc2c3bb61f4467b76d49e0af6a
  - >-
    Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee <
    b1e95e3602d8e112458627f14c6c31c21f2188cb
  - >-
    Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee <
    c3457a5aae5fb43f7023d3f3dc472c2afa22acf0
  - >-
    Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee <
    8bfe746afee38dd6e4348ddcd22d554789dbb9ff
  - >-
    Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee <
    b8282668d8fa7c61b80e8e4890729031c291a16c
  - >-
    Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee <
    565038b0092f65afe384961c0f548d605bf438b9
  - >-
    Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee <
    505b6d296c486ef7d1274f279d4c43a172f63224
  - Linux cf3d9717a5271573fa193c4dfa0df856295d5b15
  - Linux 187a6daf5db45adc807c85bbe285319107bed198
  - Linux d9897bb66ce989325b4bf4cdbb6a799e4ac878b6
  - Linux >= 4.19.162 < 4.20
  - Linux >= 5.4.82 < 5.5
  - Linux >= 5.9.13 < 5.10
  - Linux 5.10
published: '2026-09-11'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T12:01:02.225Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89562'
references:
  - url: 'https://git.kernel.org/stable/c/cb1afd087aedc90e5274537e4fb9bf3f98e5afdb'
  - url: 'https://git.kernel.org/stable/c/7719f6e7ed2ffddc2c3bb61f4467b76d49e0af6a'
  - url: 'https://git.kernel.org/stable/c/b1e95e3602d8e112458627f14c6c31c21f2188cb'
  - url: 'https://git.kernel.org/stable/c/c3457a5aae5fb43f7023d3f3dc472c2afa22acf0'
  - url: 'https://git.kernel.org/stable/c/8bfe746afee38dd6e4348ddcd22d554789dbb9ff'
  - url: 'https://git.kernel.org/stable/c/b8282668d8fa7c61b80e8e4890729031c291a16c'
  - url: 'https://git.kernel.org/stable/c/565038b0092f65afe384961c0f548d605bf438b9'
  - url: 'https://git.kernel.org/stable/c/505b6d296c486ef7d1274f279d4c43a172f63224'
tags:
  - cve.org
epss: 0.00176
epssPercentile: 0.06372
ingestedAt: '2026-09-14T15:23:07.451Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

ip6_gre: fix hardware header length for NBMA tunnels

ip6gre_tnl_link_config_route() accumulates the lower device's hardware
header length into dev->hard_header_len whenever header_ops is set. This
is incorrect for both users of header_ops.

ip6gretap and ip6erspan have a fixed Ethernet hardware header length.
For an NBMA ip6gre tunnel, ip6gre_header() creates only the GRE header,
the optional FOU or GUE header, and the outer IPv6 header. The lower
device header is headroom needed later, not part of the tunnel device's
hardware header.

Keep the lower device header in needed_headroom. Set hard_header_len to
the tunnel header length only for ARPHRD_IP6GRE devices with header_ops,
and leave the fixed Ethernet header length unchanged for tap and erspan
devices.

## Affected

- `Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee < cb1afd087aedc90e5274537e4fb9bf3f98e5afdb`
- `Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee < 7719f6e7ed2ffddc2c3bb61f4467b76d49e0af6a`
- `Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee < b1e95e3602d8e112458627f14c6c31c21f2188cb`
- `Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee < c3457a5aae5fb43f7023d3f3dc472c2afa22acf0`
- `Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee < 8bfe746afee38dd6e4348ddcd22d554789dbb9ff`
- `Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee < b8282668d8fa7c61b80e8e4890729031c291a16c`
- `Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee < 565038b0092f65afe384961c0f548d605bf438b9`
- `Linux >= 832ba596494b2c9eac7760259eff2d8b7dcad0ee < 505b6d296c486ef7d1274f279d4c43a172f63224`
- `Linux cf3d9717a5271573fa193c4dfa0df856295d5b15`
- `Linux 187a6daf5db45adc807c85bbe285319107bed198`
- `Linux d9897bb66ce989325b4bf4cdbb6a799e4ac878b6`
- `Linux >= 4.19.162 < 4.20`
- `Linux >= 5.4.82 < 5.5`
- `Linux >= 5.9.13 < 5.10`
- `Linux 5.10`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.