CVE-2023-45931 – CVE-2023-45931 is a disputed NULL pointer deref... (How to Fix)

Q: What is the severity of CVE-2023-45931?

CVE-2023-45931 has a CVSS score of 7.5 (HIGH). CVE-2023-45931 is a disputed NULL pointer dereference vulnerability in Mesa's check_xshm() function when the has_error state is triggered. This could potentially cause application crashes or denial of service in systems using Mesa graphics libraries. The vulnerability is disputed because no practical exploitation scenario has been demonstrated.

📋 TL;DR

CVE-2023-45931 is a disputed NULL pointer dereference vulnerability in Mesa's check_xshm() function when the has_error state is triggered. This could potentially cause application crashes or denial of service in systems using Mesa graphics libraries. The vulnerability is disputed because no practical exploitation scenario has been demonstrated.

💻 Affected Systems

Products:

Mesa 3D Graphics Library

Versions: 23.0.4 specifically mentioned; potentially earlier versions with similar code

Operating Systems: Linux distributions using Mesa, BSD systems with Mesa

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems using X11 with SHM extension; Wayland systems are not affected. The vulnerability is disputed and may not be practically exploitable.

📦 What is this software?

Mesa by Mesa3d

View all CVEs affecting Mesa →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Application crash leading to denial of service, potentially affecting graphical applications or services relying on Mesa graphics libraries.

🟠

Likely Case

Application instability or crash in specific edge-case scenarios, though exploitation appears difficult based on the disputed nature.

🟢

If Mitigated

Minimal impact with proper error handling and system hardening; most systems would experience no issues.

🌐 Internet-Facing: LOW - Mesa is primarily a graphics library used locally; internet-facing exposure is minimal.

🏢 Internal Only: MEDIUM - Internal systems running graphical applications with Mesa could experience instability if vulnerable.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Proof-of-concept code exists but requires specific conditions to trigger; the vulnerability is disputed with no demonstrated practical exploitation.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Mesa 23.0.5 and later

Vendor Advisory: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9859

Restart Required: Yes

Instructions:

1. Update Mesa package using your distribution's package manager. 2. For source builds: download latest Mesa source and recompile. 3. Restart graphical applications or reboot system.

🔧 Temporary Workarounds

Disable X11 SHM extension

linux

Prevents triggering the vulnerable code path by disabling the SHM extension

export XLIB_SKIP_ARGB_VISUALS=1

🧯 If You Can't Patch

Implement application sandboxing to limit impact of potential crashes
Monitor system logs for Mesa-related crashes and implement automated recovery

🔍 How to Verify

Check if Vulnerable:

Check Mesa version: glxinfo | grep 'OpenGL version string' or mesa-version command

Check Version:

glxinfo | grep 'OpenGL version string' || mesa-version || apt-cache policy mesa-utils

Verify Fix Applied:

Verify Mesa version is 23.0.5 or later and test graphical applications for stability

📡 Detection & Monitoring

Log Indicators:

Segmentation faults in X11 applications
Mesa library crash logs
X server error messages related to SHM

Network Indicators:

None - local vulnerability only

SIEM Query:

source="system_logs" AND ("segmentation fault" AND "mesa" OR "X11" AND "crash")

📊 Metadata

CVE ID: CVE-2023-45931

CVSS v3 Score: 7.5 (HIGH)

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

CWE: CWE-476

Published: March 27, 2024

Last Updated: November 4, 2025

🔗 References

https://gitlab.freedesktop.org/mesa/mesa/-/issues/9859 Exploit,Vendor Advisory
https://seclists.org/fulldisclosure/2024/Jan/71 Mailing List,Third Party Advisory
http://packetstormsecurity.com/files/176813/Mesa-23.0.4-Null-Pointer.html
http://seclists.org/fulldisclosure/2024/Jan/59
http://seclists.org/fulldisclosure/2024/Jan/71
https://gitlab.freedesktop.org/mesa/mesa/-/issues/9859 Exploit,Vendor Advisory
https://seclists.org/fulldisclosure/2024/Jan/71 Mailing List,Third Party Advisory

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