Critical Stack-Based Buffer Overflow in Apache HTTP Server (apache2) - CVE-2026-63292
Summary
DEBIAN-CVE-2026-63292: Stack-based buffer overflow in mod_vhost_alias in Apache Software Foundation Apache HTTP Server through 2.4.68 on all platforms allows a remote client to cause a denial of service or potentially execute arbitrary code vi... Affects apache2 versions 2.4.57-2 – 2.4.69-1. No fix is published. How to fix ↓
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Background
Apache HTTP Server, developed by the Apache Software Foundation, is a widely-used open-source web server software that enables the hosting of websites and web applications. It is known for its flexibility, security features, and support for various protocols. However, the server is vulnerable to a stack-based buffer overflow in the mod_vhost_alias module, which can be exploited under specific conditions, particularly when the LimitRequestFieldSize directive is configured above its default value.
Vulnerability Detail
The vulnerability, identified as CVE-2026-63292, is a stack-based buffer overflow in the mod_vhost_alias module of Apache HTTP Server versions up to 2.4.68. It allows a remote attacker to send an HTTP request with a Host header exceeding 8192 bytes, potentially leading to a denial of service or arbitrary code execution. This vulnerability arises when the VirtualDocumentRoot directive uses a hostname format specifier, making it critical for users to address it promptly to prevent exploitation.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, users can lower the LimitRequestFieldSize directive below the threshold that triggers the vulnerability. This can be done by adding the following line to your Apache configuration file: LimitRequestFieldSize 8192. However, this is not a permanent solution and upgrading is strongly recommended.
Conclusion
CVE-2026-63292 represents a significant security risk for users of Apache HTTP Server versions up to 2.4.68. It is crucial to upgrade to version 2.4.69 or later to mitigate the risk of exploitation. Users should also consider implementing workarounds temporarily while ensuring that their systems are monitored for vulnerabilities.
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FAQ
CVE-2026-63292 is a vulnerability in the Apache HTTP Server that allows for a stack-based buffer overflow, potentially leading to denial of service or arbitrary code execution.
If you are using Apache HTTP Server version 2.4.68 or earlier, your installation is vulnerable to CVE-2026-63292.
Failure to address this vulnerability can result in service disruptions or unauthorized access to your server, leading to potential data breaches.
Yes, tools like Vulert can monitor your software for open-source vulnerabilities in real-time using a manifest file. You can check if your application is affected by visiting the Vulert playground.
The CVSS score for CVE-2026-63292 is 7.5, indicating a high severity level.
References
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