CVE-2021-23974

Name of the Vulnerable Software and Affected Versions: Firefox versions prior to 86

Description: The DOMParser API did not properly process '' elements for escaping, which could be used as an mXSS vector to bypass an HTML Sanitizer.

Recommendations: For Firefox versions prior to 86, update to version 86 or later to resolve the issue. As a temporary workaround, consider restricting the use of the DOMParser API until a patch is available. Avoid using the DOMParser API to process user-supplied HTML content that may contain '' elements until the issue is resolved.