---
id: CVE-2026-80978
title: 'kernel: net: cap advertised IP tunnel headroom (CVE-2026-80978)'
summary: >-
  A flaw was found in the Linux kernel, specifically within its IP tunnel
  devices. A local attacker could create a stack of user-controlled IP tunnel
  devices, causing the system to miscalculate the required memory for network
  packet headers.…
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-787
  - CWE-190
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 6
  - enterprise_linux 7
  - enterprise_linux 8
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-10-24'
sourceUpdated: '2026-10-24T04:58:04+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80978.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80978.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-80978'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532487'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-80978'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80978'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80978.mbox
  - url: 'https://kernelcve.org/list/?q=CVE-2026-80978'
  - url: 'https://git.kernel.org/stable/c/fb889a619723032140f5d983a3a34d25a5a2bed4'
  - url: 'https://git.kernel.org/stable/c/b160422f8103574425e2834130e169d84c94fa1d'
  - url: 'https://git.kernel.org/stable/c/d36e75f5669140b66515ad3a176ca6337bd80a5e'
  - url: 'https://git.kernel.org/stable/c/84783961cb8bdb36b4f41a02ce43aafc6d52b176'
  - url: 'https://git.kernel.org/stable/c/bc4e05ae66c9797a0972ac44326e69c5305e0020'
  - url: 'https://git.kernel.org/stable/c/af0ee8f04bea22cdb331fa3509e17f81b48938ad'
  - url: 'https://git.kernel.org/stable/c/9144f2c53a04465a6878172b523f640313c5559e'
  - url: 'https://git.kernel.org/stable/c/6b222adeb9340306e2ff97127c76117abb9b3df8'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00129
epssPercentile: 0.02537
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T19:21:45.426777Z'
scores:
  vendor: 7
  cna: 7.8
ingestedAt: '2026-09-14T15:23:07.454Z'
---

## Overview

A flaw was found in the Linux kernel, specifically within its IP tunnel devices. A local attacker could create a stack of user-controlled IP tunnel devices, causing the system to miscalculate the required memory for network packet headers. This miscalculation can lead to unnecessary memory reallocations during packet transmission, which may result in performance degradation for network operations.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-10-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80978.json)

**kernel: net: cap advertised IP tunnel headroom** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-10-24.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

## Remediation

Out of support scope

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.