Critical Vulnerability in xorg-x11-server: Denial of Service and Memory Corruption Risks
Summary
RLSA-2026:11388: Important: xorg-x11-server security update. Affects xorg-x11-server versions < 0:1.20.11-33.el9_7. Fixed in 0:1.20.11-33.el9_7. How to fix ↓
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Background
The xorg-x11-server is an essential component of the X Window System, providing the foundational low-level functionality required for graphical user interfaces. It enables the display of graphical elements and user interactions in various Linux environments. This package is widely used in many distributions, including Rocky Linux, and is critical for the operation of graphical applications. However, it has recently been identified as vulnerable to several security issues that could compromise system stability and security.
Vulnerability Detail
The xorg-x11-server has multiple vulnerabilities that can lead to severe consequences. The first issue is a denial of service caused by an integer underflow in the XKB compatibility map handling (CVE-2026-33999). This can allow an attacker to crash the server, rendering the graphical interface unusable. The second vulnerability is a use-after-free condition that may lead to server crashes and potential memory corruption (CVE-2026-34001). Lastly, there is an information exposure and denial of service risk due to out-of-bounds memory access (CVE-2026-34003). These vulnerabilities can be exploited by malicious actors to disrupt services or gain unauthorized access to sensitive information.
How To Fix
Minimum fixed version
0:1.20.11-33.el9_7
This is the first release that contains the fix.
sudo dnf update xorg-x11-serverTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary measure, users can limit access to the graphical interface or disable the xwayland feature until the package is updated. This can be done by modifying the configuration files or using system settings to restrict access.
Conclusion
The xorg-x11-server has critical vulnerabilities that pose significant risks to system stability and security. It is essential to update to the latest patched version to mitigate these risks. Users should also consider using tools like Vulert to monitor for vulnerabilities in their software.
See every vulnerability recorded for xorg-x11-server →
FAQ
The CVSS score for this vulnerability is 7.8, indicating a high level of severity.
You can use Vulert's playground at Vulert Scanner to check if your application is affected without needing to sign up.
The vulnerabilities can lead to denial of service, server crashes, and potential memory corruption, which can compromise system stability and security.
Yes, Vulert can monitor and alert you in real-time for open-source vulnerabilities using just a manifest file like package-lock.json.
If you cannot update the package immediately, consider implementing workarounds such as limiting access to the graphical interface or disabling xwayland.
References
Related vulnerabilities
Recent vulnerabilities recorded for xorg-x11-server.
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