CVE-2020-26956 Explained : Impact and Mitigation

A vulnerability in Firefox, Firefox ESR, and Thunderbird could lead to XSS attacks.

Understanding CVE-2020-26956

This CVE involves a security issue in Mozilla products that could result in cross-site scripting (XSS) attacks.

What is CVE-2020-26956?

This vulnerability arises from the improper removal of HTML elements during sanitization, allowing existing SVG event handlers to persist, creating an XSS risk.

The Impact of CVE-2020-26956

The vulnerability affects Firefox versions prior to 83, Firefox ESR versions before 78.5, and Thunderbird versions below 78.5.

Technical Details of CVE-2020-26956

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The issue allows malicious actors to execute XSS attacks by retaining SVG event handlers during HTML sanitization.

Affected Systems and Versions

Firefox < 83
Firefox ESR < 78.5
Thunderbird < 78.5

Exploitation Mechanism

The vulnerability can be exploited through manual or clipboard API paste actions, enabling XSS attacks.

Mitigation and Prevention

Protect your systems from CVE-2020-26956 with these security measures.

Immediate Steps to Take

Update Firefox, Firefox ESR, and Thunderbird to versions 83, 78.5, and 78.5 respectively.
Avoid pasting untrusted content from the clipboard.

Long-Term Security Practices

Regularly update software to the latest versions.
Educate users on safe browsing practices to prevent XSS attacks.

Patching and Updates

Apply security patches provided by Mozilla to address the vulnerability.