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Advisory severityMedium6.1Vendor: HighRed Hat Linux

Medium [CVE-2025-49177] Xorg-x11-server-xwayland: xorg-x11-server: tigervnc: data leak in xfixes extension's xfixessetclientdisconnectmode

This medium-severity Red Hat Linux advisory covers CVE-2025-49177 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9.4 Extended Update Support, Red Hat Enterprise Linux 6.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2025-49177 Source published Source updated

VulniPulse record published

CVE-2025-49177
Affected products & platforms
Red Hat LinuxRed Hat Enterprise Linux
Open source advisory

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.

This flaw can result in disclosure of uninitialized memory contents from prior operations, potentially exposing sensitive information from other clients or internal server state. While this issue primarily affects confidentiality, it may also impact availability if the invalid read leads to a crash.

Red Hat severity: Important — CVSS 6.1 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L). Weakness: CWE-200.

Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9; Red Hat Enterprise Linux 9.4 Extended Update Support; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8.

Will not fix / out of support: Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Red Hat fixing advisory: RHSA-2025:9304, RHSA-2025:9303, RHSA-2025:10258.

Affected products named by the advisory: Red Hat package: xorg-x11-server-xwayland; Red Hat package: tigervnc.

Is CVE-2025-49177 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2025-49177 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2025-49177?

Upgrade to a fixed release named by Red Hat:

  • xorg-x11-server-Xwayland-0:24.1.5-4.el10_0
  • xorg-x11-server-0:1.20.11-31.el9_6
  • xorg-x11-server-Xwayland-0:23.2.7-4.el9_6
  • xorg-x11-server-Xwayland-0:22.1.9-6.el9_4
  • RHSA-2025:9304
  • RHSA-2025:9303
  • RHSA-2025:10258

Confirm against the vendor advisory before you patch.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · high-confidence parse· fetched 6 days ago·verify at source

Fixed versions
  • xorg-x11-server-Xwayland-0:24.1.5-4.el10_0
  • xorg-x11-server-0:1.20.11-31.el9_6
  • xorg-x11-server-Xwayland-0:23.2.7-4.el9_6
  • xorg-x11-server-Xwayland-0:22.1.9-6.el9_4
  • RHSA-2025:9304
  • RHSA-2025:9303
  • RHSA-2025:10258

Official advisory · high-confidence parse· fetched 6 days ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Official advisory · high-confidence parse· fetched 6 days ago·verify at source

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