CVE-2021-25978 : Security Advisory and Response

Apostrophe CMS versions between 2.63.0 to 3.3.1 are vulnerable to Stored Cross-Site Scripting (XSS) attack where an editor uploads a specially crafted SVG file containing malicious JavaScript, triggering XSS when viewed.

Understanding CVE-2021-25978

This CVE identifies a Stored XSS vulnerability in Apostrophe CMS versions between 2.63.0 to 3.3.1.

What is CVE-2021-25978?

Apostrophe - Stored XSS vulnerability occurs when an attacker injects malicious scripts into an SVG file uploaded to the Images module, leading to XSS execution upon viewing.

The Impact of CVE-2021-25978

With a CVSS base score of 5.4 (Medium), this vulnerability could be exploited by attackers to execute arbitrary JavaScript code in the context of the user's session, potentially compromising sensitive data.

Technical Details of CVE-2021-25978

This section delves into the specifics of the vulnerability.

Vulnerability Description

The vulnerability allows malicious actors to insert JavaScript code into SVG files that can execute when opened in the Images module, leading to XSS attacks.

Affected Systems and Versions

Apostrophe CMS versions 2.63.0 to 3.3.1 are impacted by this vulnerability.

Exploitation Mechanism

An attacker uploads a specially crafted SVG file containing malicious JavaScript code to the Images module, which triggers XSS when the file is viewed.

Mitigation and Prevention

To safeguard your systems from CVE-2021-25978, consider the following mitigation strategies.

Immediate Steps to Take

Upgrade Apostrophe CMS to version 3.4.0 to address the vulnerability and prevent exploitation.

Long-Term Security Practices

Regularly update and patch Apostrophe CMS to secure your environment against known vulnerabilities.

Patching and Updates

Stay informed about security releases and apply patches promptly to protect your systems from emerging threats.