dbcve.org
Heap-based Buffer OverflowWeakness · CWE-122

CVE-2024-21886

HIGH · 7.8 CVSS v3.1 Published 2024-02-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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 heap buffer overflow flaw was found in the DisableDevice function in the X.Org server. This issue may lead to an application crash or, in some circumstances, remote code execution in SSH X11 forwarding environments.

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 heap buffer overflow vulnerability exists in the DisableDevice function of the X.Org server. The flaw allows an attacker to overwrite heap memory beyond allocated buffers, potentially causing denial of service or achieving arbitrary code execution. This vulnerability is particularly exploitable in SSH X11 forwarding scenarios where the X.Org server processes forwarded X11 connections.

MitigationApply the vendor-supplied patch for X.Org server to fix the heap buffer overflow in DisableDevice. Prioritize patching systems that enable SSH X11 forwarding, as these face the highest exploitation risk.

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
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. Identify X.Org server installation
    Run 'dpkg -l | grep xserver-xorg' (Debian/Ubuntu) or 'rpm -qa | grep xorg-x11-server' (RHEL/CentOS) or check for /usr/bin/Xorg binary with 'which Xorg'
    Affected if X.Org server is not installed then the system is not affected
  2. Determine installed X.Org server version
    Run 'Xorg -version' or check package manager output from step 1, then compare the version number to any known affected ranges for CVE-2024-21886
    Affected if The installed version falls within the vulnerable version range for this CVE
  3. Verify if SSH X11 forwarding is enabled
    Check /etc/ssh/sshd_config for 'X11Forwarding yes' or inspect running SSH daemon configuration with 'sshd -T | grep x11forwarding'
    Affected if SSH X11 forwarding is enabled, creating the primary attack surface for this vulnerability
  4. Check if X server is accessible over network
    Inspect X.Org server configuration in /etc/X11/xorg.conf for 'Option "Listen" "tcp"' or run 'ss -lnp | grep 6000' to see if X listens on TCP port 6000
    Affected if X server accepts TCP connections, allowing remote exploitation of the heap overflow

A user is affected if X.Org server is installed with a vulnerable version AND SSH X11 forwarding or TCP X connections are enabled, as these expose the DisableDevice function to attacker-controlled input.

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 the vendor-supplied patch for X.Org server to fix the heap buffer overflow in DisableDevice. Prioritize patching systems that enable SSH X11 forwarding, as these face the highest exploitation risk.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA3.0 h
18.0 hours of engineering $3,120
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,992.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2024-21886 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2024-21886 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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