CVE-2021-26925 : What You Need to Know

Roundcube before 1.4.11 allows XSS via crafted Cascading Style Sheets (CSS) token sequences during HTML email rendering.

Understanding CVE-2021-26925

This CVE involves a Cross-Site Scripting (XSS) vulnerability in Roundcube email client versions prior to 1.4.11.

What is CVE-2021-26925?

CVE-2021-26925 is a security flaw in Roundcube that enables XSS attacks through specially crafted CSS token sequences in HTML email rendering.

The Impact of CVE-2021-26925

Exploitation of this vulnerability could allow attackers to execute malicious scripts in the context of a user's webmail session, potentially leading to unauthorized access to sensitive information.

Technical Details of CVE-2021-26925

This section provides insight into the specific technical aspects of the CVE.

Vulnerability Description

The vulnerability arises due to improper handling of CSS token sequences in email content, enabling attackers to inject and execute malicious scripts.

Affected Systems and Versions

Roundcube versions prior to 1.4.11 are impacted by this vulnerability, exposing users of those versions to potential XSS attacks.

Exploitation Mechanism

Attackers can exploit this vulnerability by sending specially crafted emails containing malicious CSS token sequences that, when rendered, execute arbitrary scripts.

Mitigation and Prevention

Protecting systems from CVE-2021-26925 requires immediate action and long-term security practices.

Immediate Steps to Take

Update Roundcube to version 1.4.11 or later to patch the vulnerability.
Be cautious while opening HTML emails and avoid clicking on suspicious links or downloading attachments from unknown sources.

Long-Term Security Practices

Regularly update all software components to their latest versions to mitigate potential security risks.
Educate users about the threats of phishing emails and best practices for email security.

Patching and Updates

Stay informed about security updates released by Roundcube and promptly apply patches to ensure protection against known vulnerabilities.