---
id: CVE-2026-89538
title: >-
  kernel: SUNRPC: Reject krb5 v2 wrap tokens with oversized ec field
  (CVE-2026-89538)
summary: >-
  A flaw was found in the Linux kernel's Server Unix Remote Procedure Call
  (SUNRPC) component. A remote attacker, with a valid Generic Security Service
  (GSS) context, could send a specially crafted Kerberos v2 wrap token with an
  oversized "e…
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-131
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: '2026-09-18T21:56:06+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89538.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89538.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89538'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532114'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89538'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89538'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89538.mbox
  - url: 'https://git.kernel.org/stable/c/ac9efc29346b6942e71f0e24a3178a9121330fab'
  - url: 'https://git.kernel.org/stable/c/b5746095b59f4d11f39f08751d36bbdfd1e5deac'
  - url: 'https://git.kernel.org/stable/c/9fc6d6e6db49ab55208d5dd1c424c1d0d9aa7296'
  - url: 'https://git.kernel.org/stable/c/4abb44a29bb515df6f49123848765c70fc9b5021'
  - url: 'https://git.kernel.org/stable/c/dfcd81ab45613d45996fbf483d4ef54b0ec90ab9'
  - url: 'https://git.kernel.org/stable/c/1f9856af065b6158271687e9788407b9573fd16f'
  - url: 'https://git.kernel.org/stable/c/880effc943ed82d6811f272ed3307c222b40f4d6'
  - url: 'https://git.kernel.org/stable/c/ad484748eec0a66eac0f13ab53b3fbedb7333c91'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00755
epssPercentile: 0.53187
scores:
  vendor: 7
  cna: 9.8
ingestedAt: '2026-09-14T15:23:07.452Z'
---

## Overview

A flaw was found in the Linux kernel's Server Unix Remote Procedure Call (SUNRPC) component. A remote attacker, with a valid Generic Security Service (GSS) context, could send a specially crafted Kerberos v2 wrap token with an oversized "extra count" (ec) field. This improper handling of malformed tokens could lead to the buffer being left in a semantically invalid state, potentially causing a denial of service or other unpredictable behavior within the system.

## 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-2026-89538.json)

**kernel: SUNRPC: Reject krb5 v2 wrap tokens with oversized ec field** — 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