CVE-2021-43540 : What You Need to Know
Learn about CVE-2021-43540, a vulnerability allowing Firefox WebExtensions to install ServiceWorkers for third-party sites persistently. Update to Firefox 95 for protection.
A vulnerability in Firefox prior to version 95 allowed WebExtensions to create and install ServiceWorkers for third-party websites.
Understanding CVE-2021-43540
What is CVE-2021-43540?
WebExtensions with proper permissions could install ServiceWorkers for external sites, posing a security risk for Firefox versions below 95.
The Impact of CVE-2021-43540
This vulnerability enabled WebExtensions to persistently install ServiceWorkers for third-party websites, potentially leading to unauthorized access and data manipulation.
Technical Details of CVE-2021-43540
Vulnerability Description
Firefox versions below 95 were susceptible to WebExtensions installing persistent ServiceWorkers for external domains.
Affected Systems and Versions
- Product: Firefox
- Vendor: Mozilla
- Versions Affected: < 95
Exploitation Mechanism
By exploiting this issue, malicious actors could install ServiceWorkers on websites without proper consent, bypassing typical extension constraints.
Mitigation and Prevention
Immediate Steps to Take
- Update Firefox to version 95 or newer to mitigate this vulnerability.
- Regularly review and manage browser extensions to ensure security.
Long-Term Security Practices
- Verify extension permissions before installation to prevent unauthorized actions.
- Monitor browser behavior for unusual activities that could indicate malicious actions.
Patching and Updates
Mozilla has released Firefox version 95 to address this vulnerability. Ensure prompt installation of security updates.