CVE-2021-43818 : Security Advisory and Response
Discover the impact of CVE-2021-43818, a high-severity vulnerability in lxml HTML Cleaner allowing crafted scripts to pass through. Learn mitigation steps and the affected version.
lxml is a library for processing XML and HTML in Python. Prior to version 4.6.5, a vulnerability in the HTML Cleaner allows crafted scripts and SVG embedded scripts to pass through, posing a high-risk threat.
Understanding CVE-2021-43818
lxml library's HTML Cleaner vulnerability.
What is CVE-2021-43818?
lxml library prior to 4.6.5 is vulnerable to crafted script content and SVG script content in data URIs passing through the HTML Cleaner, potentially leading to security breaches.
The Impact of CVE-2021-43818
The vulnerability has a CVSS base score of 8.2, with high severity due to allowing crafted scripts to bypass security measures, impacting integrity and confidentiality.
Technical Details of CVE-2021-43818
Details of the vulnerability and its implications.
Vulnerability Description
- lxml library before 4.6.5 HTML Cleaner flaw
- Crafted script content can bypass security
Affected Systems and Versions
- Affected version: < 4.6.5
Exploitation Mechanism
- Attacker crafts malicious scripts in HTML content
- Scripts can be embedded in SVG using data URIs
Mitigation and Prevention
Protective measures against CVE-2021-43818.
Immediate Steps to Take
- Upgrade to lxml 4.6.5 or higher
- Avoid using the HTML Cleaner in sensitive contexts
Long-Term Security Practices
- Regularly update the lxml library
- Implement input validation and sanitization practices
Patching and Updates
- Apply patches promptly to ensure vulnerability resolution