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Enterprise LinuxOperating system · Redhat

CVE-2025-26594

HIGH · 7.8 CVSS v3.1 Published 2025-02-25
Fix available
A fix is available. Upgrade to 21.1.16 / 24.1.6 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A use-after-free flaw was found in X.Org and Xwayland. The root cursor is referenced in the X server as a global variable. If a client frees the root cursor, the internal reference points to freed memory and causes a use-after-free.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A use-after-free vulnerability exists in X.Org and Xwayland servers where the root cursor is stored as a global variable. When a client frees the root cursor, the internal server reference continues pointing to the freed memory location, allowing potential exploitation of the use-after-free condition for code execution.

MitigationApply vendor patches for X.Org and Xwayland when available; until then, restrict untrusted client access to the X server to prevent triggering the vulnerable code path.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Enterprise LinuxOperating system
Affected:= 7.0= 8.0= 9.0
TigervncApplication
Affected:all versions
X ServerApplication
Affected:< 21.1.16
XwaylandApplication
Affected:< 24.1.6

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check X.org X Server version
    Run 'Xorg -version' or 'rpm -q xorg-x11-server' to determine the installed X Server version
    Affected if Version is lower than 21.1.16 (e.g., 21.1.15, 21.1.14, 21.1.13, 21.1.12, 21.1.11, 21.1.10, 21.1.9, 21.1.8, 21.1.7, 21.1.6, 21.1.5, 21.1.4, 21.1.3, 21.1.2, 21.1.1, 21.1.0, or any 20.x/19.x/18.x release)
  2. Check Xwayland version
    Run 'Xwayland --version' or 'rpm -q xwayland' to determine the installed Xwayland version
    Affected if Version is lower than 24.1.6 (e.g., 24.1.5, 24.1.4, 24.1.3, 24.1.2, 24.1.1, 24.1.0, or any 23.x/22.x/21.x release)
  3. Check if Tigervnc is installed
    Run 'rpm -q tigervnc' or 'rpm -q tigervnc-server' to check for Tigervnc installation
    Affected if Tigervnc is installed (all versions are affected per the advisory)
  4. Check Red Hat Enterprise Linux version
    Run 'cat /etc/redhat-release' or 'rpm -q redhat-release' to identify the RHEL version
    Affected if Running RHEL 7.0, 8.0, or 9.0 (specific affected versions per the advisory)

You are affected if you run X.org X Server < 21.1.16, Xwayland < 24.1.6, any version of Tigervnc, or RHEL 7.0/8.0/9.0 with the vulnerable X components.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 21.1.16 / 24.1.6 or later
Fixed in 21.1.1624.1.6
Interim mitigation

Apply vendor patches for X.Org and Xwayland when available; until then, restrict untrusted client access to the X server to prevent triggering the vulnerable code path.

Recommended fix Moderate confidence

X Server 21.1.16, Xwayland 24.1.6, or latest available in your distribution's repository

  1. For X Server: Upgrade to X Server version 21.1.16 or later
  2. For Xwayland: Upgrade to Xwayland version 24.1.6 or later
  3. For RHEL/CentOS systems: Apply the latest security updates via 'dnf update' or 'yum update' to receive the patched packages
  4. Verify the installed versions with 'Xorg -version' and 'Xwayland --version' after updating
  5. Restart X server or graphical session for changes to take effect
Caveat Review release notes for X Server 21.1.16 and Xwayland 24.1.6 for any compatibility or behavioral changes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Enterprise Linux Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,280
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-26594 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data