Critical Security Flaw in mod_http2 Package: Use After Free and Out-of-Bounds Read Vulnerabilities
Summary
ALSA-2026:59387: Moderate: mod_http2 security, bug fix, and enhancement update. Affects mod_http2 versions < 2.0.26-6.el9_8.2. Fixed in 2.0.26-6.el9_8.2. How to fix ↓
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Background
The mod_http2 package is an Apache HTTP Server module that implements the HTTP/2 protocol, enhancing the performance and efficiency of web communications. It leverages the libnghttp2 library to support both h2 and h2c protocols. This package is crucial for modern web applications that require faster data transfer and improved resource management. However, recent vulnerabilities have been identified that could compromise the security of systems utilizing this module.
Vulnerability Detail
The vulnerabilities in mod_http2 stem from a Use After Free issue that allows attackers to execute arbitrary code or cause a denial of service. Additionally, an Out-of-Bounds Read vulnerability in mod_headers and mod_mime can lead to information disclosure. These vulnerabilities arise from improper memory management and insufficient input validation, posing significant risks to the integrity and availability of affected systems.
How To Fix
Minimum fixed version
2.0.26-6.el9_8.2
This is the first release that contains the fix.
sudo dnf update mod_http2Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can disable the mod_http2 module until the package is updated. This can be done by executing the command: 'sudo a2dismod http2' followed by
sudo systemctl restart httpd' to restart the Apache server.
Conclusion
The mod_http2 package has been found to contain critical vulnerabilities that could lead to severe security risks. It is imperative for users to update to the latest patched version to safeguard their systems. Additionally, temporary workarounds are available for those unable to update immediately. Regular monitoring for vulnerabilities using tools like Vulert can help maintain the security of your applications.
See every vulnerability recorded for mod_http2 →
FAQ
The Use After Free vulnerability can allow attackers to execute arbitrary code on the server, potentially leading to full system compromise.
You can use Vulert's playground at Vulert Scanner to check if your application is affected without needing to sign up.
If an immediate update is not possible, consider disabling the mod_http2 module as a temporary measure to mitigate risks.
While specific exploits may not be publicly disclosed, the nature of these vulnerabilities makes them attractive targets for attackers.
The recommended version to mitigate these vulnerabilities is 2.0.26-6.el9_8.2 or later.
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