CVE-2021-38503 : Security Advisory and Response

A detailed overview of CVE-2021-38503 affecting Firefox, Thunderbird, and Firefox ESR.

Understanding CVE-2021-38503

This vulnerability involves the incorrect application of iframe sandbox rules to XSLT stylesheets in Mozilla products.

What is CVE-2021-38503?

The iframe sandbox rules were not correctly applied to XSLT stylesheets, enabling an iframe to bypass security restrictions on executing scripts or navigating the top-level frame.

The Impact of CVE-2021-38503

The vulnerability affects Firefox versions prior to 94, Thunderbird versions before 91.3, and Firefox ESR versions less than 91.3.

Technical Details of CVE-2021-38503

Learn more about the specifics of this security issue.

Vulnerability Description

The issue allows an iframe to evade security restrictions on scripts and frame navigation in affected Mozilla products.

Affected Systems and Versions

Firefox < 94, Thunderbird < 91.3, Firefox ESR < 91.3 are impacted by this vulnerability.

Exploitation Mechanism

Attackers can exploit this flaw to execute malicious scripts and potentially navigate users to malicious websites.

Mitigation and Prevention

Discover the steps to mitigate the risks posed by CVE-2021-38503.

Immediate Steps to Take

Users should update their Firefox, Thunderbird, and Firefox ESR installations to the latest versions to prevent exploitation.

Long-Term Security Practices

Enforce strict browsing habits and caution while interacting with unfamiliar websites or links.

Patching and Updates

Regularly check for security updates and apply patches promptly to stay protected from known vulnerabilities.