Critical NULL Pointer Dereference in libxml2 Leading to Segfault
Summary
DEBIAN-CVE-2023-28484: In libxml2 before 2.10.4, parsing of certain invalid XSD schemas can lead to a NULL pointer dereference and subsequently a segfault. Affects libxml2 versions < 2.9.10+dfsg-6.7+deb11u4. Fixed in 2.9.10+dfsg-6.7+deb11u4. How to fix ↓
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Background
libxml2 is a widely used XML parsing library that provides a range of functionalities for processing XML and HTML documents. It is known for its performance and compliance with standards, making it a crucial component in many applications. However, versions prior to 2.10.4 are vulnerable to a specific issue that can cause a NULL pointer dereference when parsing certain invalid XSD schemas, potentially leading to application crashes.
Vulnerability Detail
In libxml2 before version 2.10.4, a vulnerability exists in the function xmlSchemaFixupComplexType within xmlschemas.c. This vulnerability arises when the library attempts to parse certain malformed XSD schemas, resulting in a NULL pointer dereference. The consequence of this issue is a segmentation fault (segfault), which can crash the application using the library. This vulnerability poses a significant risk, especially for applications that rely on XML schema validation, as it can lead to unexpected behavior and service disruptions.
How To Fix
Minimum fixed version
2.9.10+dfsg-6.7+deb11u4
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
If immediate patching is not feasible, consider implementing input validation to ensure that only well-formed XSD schemas are processed by the application. This can help prevent the parsing of invalid schemas that trigger the vulnerability.
Conclusion
The vulnerability in libxml2 poses a significant risk due to the potential for application crashes when processing invalid XSD schemas. It is crucial for users to update to the latest patched versions to ensure the security and stability of their applications. Additionally, implementing input validation can serve as a temporary workaround until the update is applied.
See every vulnerability recorded for libxml2 →
FAQ
libxml2 is an open-source library for parsing XML and HTML documents, providing a variety of functionalities for developers.
The NULL pointer dereference occurs when libxml2 attempts to parse certain invalid XSD schemas, leading to a segmentation fault.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software. You can check your application using the Vulert playground without any signup.
The vulnerability can lead to application crashes, resulting in service disruptions and potential data loss.
It is recommended to regularly check for updates and apply patches as soon as they are available to minimize security risks.
References
Related vulnerabilities
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