---
id: CVE-2026-89761
title: >-
  kernel: apparmor: fix out-of-bounds write when null terminating a label vec
  (CVE-2026-89761)
summary: >-
  A flaw was found in the Linux kernel's AppArmor security module. An
  out-of-bounds write vulnerability exists when null terminating a label vector
  due to improper memory allocation. An unprivileged local attacker can exploit
  this by writing…
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
vendor: Red Hat
product: Linux
affected:
  - >-
    Linux >= f1bd904175e8190ce14aedee37e207ab51fe3b30 <
    9124e078ea2250d8d01d2162a550acb01ef5bf48
  - >-
    Linux >= f1bd904175e8190ce14aedee37e207ab51fe3b30 <
    28069434aef66b9d084f0609b7a29c171846815e
  - >-
    Linux >= f1bd904175e8190ce14aedee37e207ab51fe3b30 <
    36bdd0b45ec3f4822832a56e9db8674c8450dfce
  - >-
    Linux >= f1bd904175e8190ce14aedee37e207ab51fe3b30 <
    9f1e40193eef7f047e6b77cfb4b4cafdecd7a123
  - Linux 4.13
published: '2026-09-11'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T18:29:12+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89761.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89761.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89761'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532235'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89761'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89761'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89761.mbox
  - url: 'https://git.kernel.org/stable/c/9124e078ea2250d8d01d2162a550acb01ef5bf48'
  - url: 'https://git.kernel.org/stable/c/28069434aef66b9d084f0609b7a29c171846815e'
  - url: 'https://git.kernel.org/stable/c/36bdd0b45ec3f4822832a56e9db8674c8450dfce'
  - url: 'https://git.kernel.org/stable/c/9f1e40193eef7f047e6b77cfb4b4cafdecd7a123'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00175
epssPercentile: 0.06235
scores:
  vendor: 5.5
  cna: 7.8
ingestedAt: '2026-09-14T15:23:07.472Z'
---

## Overview

A flaw was found in the Linux kernel's AppArmor security module. An out-of-bounds write vulnerability exists when null terminating a label vector due to improper memory allocation. An unprivileged local attacker can exploit this by writing to specific system files, potentially leading to a denial of service (DoS) or, in some cases, privilege escalation. This vulnerability requires an AppArmor policy to be loaded on the system.

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89761.json)

**kernel: apparmor: fix out-of-bounds write when null terminating a label vec** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-21.

Not 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

## Remediation

Refer to the advisory for fix availability.