CVE-2021-43538 : Security Advisory and Response

A vulnerability in Mozilla products allows attackers to hide notifications, potentially leading to spoofing attacks.

Understanding CVE-2021-43538

What is CVE-2021-43538?

By misusing a race in Mozilla's notification code, attackers can hide notifications on specific pages, posing a risk for spoofing attacks. This vulnerability impacts Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

The Impact of CVE-2021-43538

Attackers can exploit this flaw to hide critical notifications, increasing the risk of spoofing attacks within affected Mozilla products.

Technical Details of CVE-2021-43538

Vulnerability Description

The vulnerability stems from a race condition in the notification code, allowing attackers to hide notifications related to full-screen and pointer lock access.

Affected Systems and Versions

Thunderbird < 91.4.0
Firefox ESR < 91.4.0
Firefox < 95

Exploitation Mechanism

Attackers misuse the race condition in Mozilla's notification system to hide notifications, potentially facilitating spoofing attacks.

Mitigation and Prevention

Immediate Steps to Take

Update Mozilla Thunderbird, Firefox ESR, and Firefox to versions 91.4.0 and above.
Stay vigilant for any suspicious activities or notifications on affected systems.

Long-Term Security Practices

Conduct regular security audits to detect and address vulnerabilities promptly.
Educate users on the importance of verifying notifications and staying informed about security updates.

Patching and Updates

Apply security patches provided by Mozilla to ensure that the vulnerability is addressed and systems are secure.