Critical Use-After-Free Vulnerability in libxml2: Potential Crash and Undefined Behavior
Summary
CVE-2025-49794: A use-after-free vulnerability was found in libxml2. Affects libxml2 versions < 2.9.10+dfsg-6.7+deb11u8. Fixed in 2.9.10+dfsg-6.7+deb11u8. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
libxml2 is a widely used XML parsing library that provides a range of functionalities for processing XML documents. It is known for its speed and efficiency, making it a popular choice among developers for applications that require XML manipulation. However, libxml2 has been found to have a critical vulnerability that can lead to severe consequences if exploited.
Vulnerability Detail
A use-after-free vulnerability exists in libxml2 when parsing XPath elements under specific conditions involving the XML schematron with <sch:name path="..."/> schema elements. This flaw allows an attacker to craft a malicious XML document that, when processed by libxml2, can cause the program to crash or exhibit undefined behavior. The vulnerability arises from improper memory management, leading to potential exploitation and system instability.
How To Fix
Minimum fixed version
2.9.10+dfsg-6.7+deb11u8
This is the first release that contains the fix.
sudo apt-get install --only-upgrade libxml2Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, avoid processing untrusted XML documents that may contain XPath elements with <sch:name path="..."/> until the library is updated. This can help mitigate the risk of exploitation until a patch is applied.
Conclusion
The use-after-free vulnerability in libxml2 poses a significant risk to applications that rely on this library for XML processing. It is crucial for users to update to the latest version of libxml2 to protect against potential crashes and undefined behavior. Utilizing tools like Vulert can help monitor and manage vulnerabilities effectively.
See every vulnerability recorded for libxml2 →
FAQ
A use-after-free vulnerability occurs when a program continues to use a memory location after it has been freed, potentially leading to crashes or arbitrary code execution.
You can check if your application is affected by using the Vulert playground at Vulert Scanner, which allows you to monitor and alert for open-source vulnerabilities in your software without requiring installation.
Exploitation of this vulnerability can lead to application crashes, undefined behavior, and potential security breaches, allowing attackers to execute arbitrary code.
Yes, a patched version of libxml2 is available. Users should update to the latest version to mitigate the risk associated with this vulnerability.
The CVSS score of this vulnerability is 9.1, indicating a critical level of severity.
Related vulnerabilities
Recent vulnerabilities recorded for libxml2.
