Critical Vulnerability in Expat Package: Encoding Validation Flaw
Summary
UBUNTU-CVE-2022-25235: xmltok_impl.c in Expat (aka libexpat) before 2.4.5 lacks certain validation of encoding, such as checks for whether a UTF-8 character is valid in a certain context. Affects expat versions < 2.1.0-4ubuntu1.4+esm4. Fixed in 2.1.0-4ubuntu1.4+esm4. How to fix ↓
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Background
Expat is an XML parsing library widely used in various applications for its efficiency and ease of use. It provides a fast and lightweight way to parse XML documents, making it a popular choice among developers. However, a critical vulnerability has been identified in Expat, specifically in versions prior to 2.4.5, which affects its ability to validate UTF-8 character encoding. This flaw can lead to potential security risks, including denial of service and data corruption.
Vulnerability Detail
The vulnerability, identified as CVE-2022-25235, originates from the xmltok_impl.c file in Expat. It lacks adequate validation of encoding, particularly checks for whether a UTF-8 character is valid in a specific context. This oversight can allow attackers to exploit the library, potentially leading to severe consequences such as application crashes or unexpected behavior. The CVSS score for this vulnerability is 9.8, indicating a critical severity level.
How To Fix
Minimum fixed version
2.1.0-4ubuntu1.4+esm4
This is the first release that contains the fix.
sudo apt-get install --only-upgrade expatTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can avoid using the affected features of the Expat library until the package is updated. Additionally, implementing input validation on XML data before processing it with Expat can help mitigate some risks associated with this vulnerability.
Conclusion
The Expat package has a critical vulnerability that can severely impact applications using it. It is crucial for users to update to the patched version to safeguard their systems. Regular monitoring and validation practices should be implemented to prevent potential exploitation of such vulnerabilities.
See every vulnerability recorded for expat →
FAQ
CVE-2022-25235 is a critical vulnerability in the Expat XML parsing library that arises from inadequate validation of UTF-8 character encoding.
You can use Vulert, which monitors and alerts in real-time for open-source vulnerabilities. By uploading your manifest file like package-lock.json, you can check if your application is affected.
The vulnerability can lead to denial of service, data corruption, and unexpected application behavior, posing significant security risks.
Yes, a patched version of the Expat package is available. Users should update to version 2.4.5 or later to mitigate the vulnerability.
Using tools like Vulert can help you monitor and receive alerts for open-source vulnerabilities in your software without requiring access to the code.
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