---
id: CVE-2026-89539
title: 'SUNRPC: reject duplicate CREDS_VALUE options'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  SUNRPC: reject duplicate CREDS_VALUE options

  gssx_dec_option_array() walks the wire-supplied option array and, for
  every entry whose name matches CREDS_VALUE, calls
  gs…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe:
  - CWE-772
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1d658336b05f8697d6445834f8867f8ad5e4f735 <
    4b5ebb4f91a6152a0f7b1253f701197e5710d4da
  - >-
    Linux >= 1d658336b05f8697d6445834f8867f8ad5e4f735 <
    f615b884310bf82d0014e3b5a92eb9aa88146685
  - >-
    Linux >= 1d658336b05f8697d6445834f8867f8ad5e4f735 <
    7a1d0501cbb962beba23377035d667bf3c1726ee
  - >-
    Linux >= 1d658336b05f8697d6445834f8867f8ad5e4f735 <
    9d94f046b23de0f77849ea69133063c949297e30
  - >-
    Linux >= 1d658336b05f8697d6445834f8867f8ad5e4f735 <
    2e4ce62385c1b8a887c5370af058ac7b52a8eaf9
  - Linux 3.10
published: '2026-09-11'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T12:47:46.957Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89539'
references:
  - url: 'https://git.kernel.org/stable/c/4b5ebb4f91a6152a0f7b1253f701197e5710d4da'
  - url: 'https://git.kernel.org/stable/c/f615b884310bf82d0014e3b5a92eb9aa88146685'
  - url: 'https://git.kernel.org/stable/c/7a1d0501cbb962beba23377035d667bf3c1726ee'
  - url: 'https://git.kernel.org/stable/c/9d94f046b23de0f77849ea69133063c949297e30'
  - url: 'https://git.kernel.org/stable/c/2e4ce62385c1b8a887c5370af058ac7b52a8eaf9'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89539.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89539'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532304'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89539'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89539'
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00168
epssPercentile: 0.06161
ingestedAt: '2026-09-14T11:11:19.886Z'
---

## Overview

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

SUNRPC: reject duplicate CREDS_VALUE options

gssx_dec_option_array() walks the wire-supplied option array and, for
every entry whose name matches CREDS_VALUE, calls
gssx_dec_linux_creds() on the same struct svc_cred. That helper
unconditionally installs a fresh groups_alloc() result into
creds->cr_group_info without releasing whatever pointer was already
there:

    for (i = 0; i < count; i++) {
        ... decode name ...
        if (length == sizeof(CREDS_VALUE) &&
            memcmp(p, CREDS_VALUE, sizeof(CREDS_VALUE)) == 0) {
            err = gssx_dec_linux_creds(xdr, creds);
            ...
        }
    }

A reply that carries two CREDS_VALUE entries therefore overwrites
cr_group_info on the second iteration and orphans the group_info
allocated by the first call. The earlier free_creds path only
releases the last cr_group_info via free_svc_cred(), so the first
allocation's refcount stays at one and its kvmalloc-backed storage
is leaked. No in-tree caller of gssp_accept_sec_context_upcall()
expects more than one CREDS_VALUE per reply.

Fix by tracking whether a CREDS_VALUE option has already been
decoded and returning -EINVAL on any subsequent match, so the
free_creds path releases the single group_info that was installed.

## Affected

- `Linux >= 1d658336b05f8697d6445834f8867f8ad5e4f735 < 4b5ebb4f91a6152a0f7b1253f701197e5710d4da`
- `Linux >= 1d658336b05f8697d6445834f8867f8ad5e4f735 < f615b884310bf82d0014e3b5a92eb9aa88146685`
- `Linux >= 1d658336b05f8697d6445834f8867f8ad5e4f735 < 7a1d0501cbb962beba23377035d667bf3c1726ee`
- `Linux >= 1d658336b05f8697d6445834f8867f8ad5e4f735 < 9d94f046b23de0f77849ea69133063c949297e30`
- `Linux >= 1d658336b05f8697d6445834f8867f8ad5e4f735 < 2e4ce62385c1b8a887c5370af058ac7b52a8eaf9`
- `Linux 3.10`

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat OpenShift Container Platform 4 · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89539.json)