Cross-Site Scripting Vulnerability in lxml Package
Summary
DEBIAN-CVE-2014-3146: Incomplete blacklist vulnerability in the lxml.html.clean module in lxml before 3.3.5 allows remote attackers to conduct cross-site scripting (XSS) attacks via control characters in the link scheme to the clean_html func... Affects lxml versions < 3.3.5-1. Fixed in 3.3.5-1. 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
lxml is a powerful and feature-rich library in Python that provides easy handling of XML and HTML documents. It is widely used for parsing, creating, and manipulating XML and HTML. However, prior to version 3.3.5, lxml's html.clean module had an incomplete blacklist vulnerability that allowed attackers to exploit the clean_html function.
Vulnerability Detail
The vulnerability identified as DEBIAN-CVE-2014-3146 arises from an incomplete blacklist in the lxml.html.clean module. This flaw allows remote attackers to conduct cross-site scripting (XSS) attacks by injecting control characters into the link scheme passed to the clean_html function. If exploited, this could lead to unauthorized access to sensitive information or manipulation of web content, posing a significant security risk.
How To Fix
Minimum fixed version
3.3.5-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade lxmlTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, you can sanitize input data before passing it to the clean_html function to mitigate the risk of XSS attacks. However, the best solution is to update to the patched version.
Conclusion
The lxml package has a critical vulnerability that can lead to XSS attacks if not addressed. It is crucial to update to the patched version to ensure the security of applications using this library. Utilizing tools like Vulert can help monitor and manage vulnerabilities effectively.
See every vulnerability recorded for lxml →
FAQ
The vulnerability is an incomplete blacklist issue that allows XSS attacks through control characters in the link scheme.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
If exploited, this vulnerability can lead to unauthorized access to sensitive information and manipulation of web content, posing a significant security risk.
Yes, the vulnerability is fixed in lxml version 3.3.5-1 and later. Updating to this version will resolve the issue.
Vulert monitors and alerts for open-source vulnerabilities in your software using just a manifest file like package-lock.json, providing real-time insights into potential risks.
References
Related vulnerabilities
Recent vulnerabilities recorded for lxml.
