---
id: CVE-2025-49177
title: A flaw was found in the XFIXES extension
summary: >-
  A flaw was found in the XFIXES extension. The XFixesSetClientDisconnectMode
  handler does not validate the request length, allowing a client to read
  unintended memory from previous requests.
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L'
cwe:
  - CWE-200
published: '2025-06-17'
updated: '2026-06-25'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-49177'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2025:10258'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2025:9303'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2025:9304'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2025-49177'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2369955'
    label: secalert@redhat.com
  - url: >-
      https://gitlab.freedesktop.org/xorg/xserver/-/commit/ab02fb96b1c701c3bb47617d965522c34befa6af
    label: secalert@redhat.com
  - url: 'https://www.x.org/wiki/Development/Security/'
    label: secalert@redhat.com
tags:
  - nvd
epss: 0.00429
epssPercentile: 0.34544
ingestedAt: '2026-06-29T13:24:34.376Z'
---

## Overview

A flaw was found in the XFIXES extension. The XFixesSetClientDisconnectMode handler does not validate the request length, allowing a client to read unintended memory from previous requests.

## Remediation

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