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Integer OverflowWeakness · CWE-190

CVE-2025-49179

HIGH · 7.3 CVSS v3.1 Published 2025-06-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
75/100
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 flaw was found in the X Record extension. The RecordSanityCheckRegisterClients function does not check for an integer overflow when computing request length, which allows a client to bypass length checks.

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

Integer overflow in the X11 Record extension's RecordSanityCheckRegisterClients function allows clients to bypass length validation when computing request sizes, potentially leading to buffer overflows or memory corruption in the X server.

MitigationApply available patches for CVE-2025-49179; restrict X server network access to trusted clients and disable the Record extension if not required.

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

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
Low
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/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. Verify X server is running
    Run 'ps aux | grep Xorg' or 'ps aux | grep X' to check for running X server processes. On Linux, also check 'systemctl status display-manager' or check /var/log/Xorg.0.log for recent sessions.
    Affected if X server is not running (not affected - no X11 session exists)
  2. Check if Record extension is loaded
    Run 'xdpyinfo -queryExtensions 2>/dev/null | grep -i record' or check X server logs for 'Record' extension loading. Also examine /etc/X11/xorg.conf or files in /etc/X11/xorg.conf.d/ for Load "record" directives.
    Affected if Record extension is not loaded (not affected)
  3. Determine X server version
    Run 'Xorg -version' or check 'X -version' output. Also examine /var/log/Xorg.0.log header for version information like "X.Org X Server X.Y.Z".
    Affected if Version falls within vulnerable range and Record extension is enabled - compare your version to official X.org security advisories for CVE-2025-49179 fixed versions
  4. Check X server network exposure
    Run 'ss -tlnp | grep -E "600[0-9]:"' or 'netstat -tlnp | grep X' to see if X server is listening on TCP ports. Also check 'xauth list' for network-accessible displays.
    Affected if X server is exposed to network AND Record extension is enabled (exposes attack surface to remote clients)
  5. Verify Record extension is actively used
    Review application configurations for any tools using the Record extension (xdotool, xnee, keyloggers, automation tools). Check /var/log/Xorg.0.log for "Record" extension client connections.
    Affected if No applications use the Record extension (reduced risk, though the vulnerable code is still present in memory if loaded)

User is affected if X server is running with the Record extension enabled AND the installed X server version lacks the CVE-2025-49179 patch, especially when X server is network-accessible.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply available patches for CVE-2025-49179; restrict X server network access to trusted clients and disable the Record extension if not required.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2025-49179 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
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  • Version or environment caveats, and links to real fixes
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