CVE-2021-35210 : What You Need to Know

Contao 4.5.x through 4.9.x before 4.9.16, and 4.10.x through 4.11.x before 4.11.5, allows XSS vulnerability that enables code injection into the tl_log table, leading to execution in the browser when the system log is accessed in the back end.

Understanding CVE-2021-35210

This section provides insights into the impact and technical details of the CVE-2021-35210 vulnerability.

What is CVE-2021-35210?

CVE-2021-35210 is a Cross-Site Scripting (XSS) vulnerability in Contao versions 4.5.x through 4.9.x and 4.10.x through 4.11.x, allowing malicious actors to inject and execute code via the system log.

The Impact of CVE-2021-35210

The vulnerability can be exploited to inject harmful code into the system log, which, when executed in the browser's back end, poses a significant security risk to the affected systems.

Technical Details of CVE-2021-35210

Explore the specifics of the vulnerability concerning description, affected systems, versions, and the exploitation mechanism.

Vulnerability Description

The flaw allows attackers to insert code into the tl_log table, permitting the execution of malicious scripts when the system log is accessed in the administrative interface.

Affected Systems and Versions

Contao versions 4.5.x to 4.9.x (prior to 4.9.16) and 4.10.x to 4.11.x (before 4.11.5) are impacted by this XSS vulnerability.

Exploitation Mechanism

By injecting malicious code into the system log, threat actors can trigger its execution within the browser's backend, potentially compromising system security.

Mitigation and Prevention

Discover the immediate steps to secure your system and establish long-term security practices for safeguarding against CVE-2021-35210.

Immediate Steps to Take

Users are advised to update Contao to versions 4.9.16 and 4.11.5 to mitigate the XSS vulnerability and prevent potential code injections through the system log.

Long-Term Security Practices

Implement secure coding practices, regularly update software, and conduct security audits to mitigate similar XSS risks in the future.

Patching and Updates

Stay informed about security advisories and promptly apply patches released by Contao to address vulnerabilities and enhance system security.