---
id: CVE-2026-89537
title: >-
  kernel: SUNRPC: Reject short RFC 4121 MIC tokens in gss_krb5_verify_mic_v2
  (CVE-2026-89537)
summary: >-
  A flaw was found in the Linux kernel's SUNRPC implementation, specifically
  within the `gss_krb5_verify_mic_v2` function. A remote malicious Network File
  System (NFS) server could provide a specially crafted, short Kerberos Message
  Integrit…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: vendor
cwe: CWE-125
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: '2026-09-18'
sourceUpdated: '2026-09-18T21:56:01+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89537.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89537.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89537'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532109'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89537'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89537'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89537.mbox
  - url: 'https://git.kernel.org/stable/c/7a946b2e7207f968902f2147ab9b30726f82f7ab'
  - url: 'https://git.kernel.org/stable/c/b94f6719dcd9f7a609bc5f459f85795900e77d25'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00539
epssPercentile: 0.42866
scores:
  vendor: 6.4
  cna: 9.1
ingestedAt: '2026-09-14T15:23:07.474Z'
---

## Overview

A flaw was found in the Linux kernel's SUNRPC implementation, specifically within the `gss_krb5_verify_mic_v2` function. A remote malicious Network File System (NFS) server could provide a specially crafted, short Kerberos Message Integrity Code (MIC) token. This could lead to the kernel reading past an allocated memory buffer, potentially causing a denial of service or information disclosure.

## 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 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89537.json)

**kernel: SUNRPC: Reject short RFC 4121 MIC tokens in gss_krb5_verify_mic_v2** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-18.

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