dbcve.org
Enterprise LinuxOperating system · Redhat

CVE-2023-43785

MEDIUM · 5.5 CVSS v3.1 Published 2023-10-10
Fix available
A fix is available. Upgrade to 1.8.7 or later.
See remediation →
57/100
Remediation priority · Elevated
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 vulnerability was found in libX11 due to a boundary condition within the _XkbReadKeySyms() function. This flaw allows a local user to trigger an out-of-bounds read error and read the contents of memory on the system.

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 · high confidence

libX11 contains an out-of-bounds read vulnerability in the _XkbReadKeySyms() function due to insufficient boundary checking. A local attacker can exploit this flaw to read arbitrary memory contents on the system, potentially exposing sensitive data.

MitigationApply the vendor-supplied patch or update libX11 to the fixed version. Verify the update does not introduce regressions in keyboard/X11 functionality.

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:= 8.0= 9.0
FedoraOperating system
Affected:= 38
Libx11Application
Affected:< 1.8.7

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
None
Availability
None

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

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 libX11 is installed
    Run 'rpm -qa | grep -i libx11' (RHEL/Fedora) or check for libX11.so files in /usr/lib/ and /usr/lib64/ directories
    Affected if No libX11 package or library found means not affected by this CVE
  2. Determine installed libX11 version
    Run 'rpm -q libX11' (RHEL/Fedora) or check the library version with 'objdump -p /usr/lib/libX11.so.* | grep VERSION'
    Affected if Version is less than 1.8.7 (or for RHEL 8.0/9.0 and Fedora 38, any version) - these are all affected
  3. Confirm XKB extension is in use
    Check if X11 keyboard configuration uses XKB by examining /etc/X11/xorg.conf.d/ keyboard configs, or run 'setxkbmap -print' or check X logs for XKB activity
    Affected if XKB extension is active - the vulnerability exists in the _XkbReadKeySyms function and only triggers when XKB is loaded
  4. Check for X11-related processes
    Run 'ps aux | grep X' or 'systemctl status display-manager' to verify X11 server is running
    Affected if No X11 server running means the vulnerability is not currently exploitable though the vulnerable library is still present

You are affected if libX11 version is below 1.8.7 AND the XKB extension is enabled and being used by your X11 environment.

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 1.8.7 or later
Fixed in 1.8.7
Interim mitigation

Apply the vendor-supplied patch or update libX11 to the fixed version. Verify the update does not introduce regressions in keyboard/X11 functionality.

Recommended fix High confidence

libX11 version 1.8.7 or later

  1. 1. Identify the libX11 library version currently installed on the system using: `rpm -q libX11` or `dnf list installed libX11`
  2. 2. For RHEL/Enterprise Linux systems, check for available updates: `dnf check-update` or `yum update libX11`
  3. 3. Apply the update to upgrade libX11 to version 1.8.7 or later
  4. 4. For Fedora 38 systems, run: `dnf update libX11`
  5. 5. After updating, verify the new version: `rpm -q libX11` to confirm version 1.8.7 or higher is installed
  6. 6. Restart any X11-dependent applications or services if necessary to load the patched library

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

Fix this in Enterprise Linux Scoped from the published advisory
  • Consultation4.0 h
  • Implementation3.0 h
  • Testing6.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,600
Get the upgrade done

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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-2023-43785 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