Andrea Marchesini

**Name of the Vulnerable Software and Affected Versions** Firefox versions prior to 61 Firefox ESR versions prior to 60.1 Thunderbird versions prior to 60 **Description** The issue exists due to insufficient input validation in the PerformanceNavigationTiming component of Firefox and Thunderbird. This could allow a remote attacker to disclose protected information. The vulnerability was discovered as a result of previous mitigations for Spectre, where the resolution of various methods was reduced to counteract the ability to measure precise time intervals. It was found that PerformanceNavigationTiming could be used as a precision timer. **Recommendations** For Firefox versions prior to 61, update to version 61 or later to resolve the issue. For Firefox ESR versions prior to 60.1, update to version 60.1 or later to resolve the issue. For Thunderbird versions prior to 60, update to version 60 or later to resolve the issue.

Name of the Vulnerable Software and Affected Versions: Firefox versions prior to 58 Description: The issue concerns a potential violation of origin attribute segregation through a Blob URL, which could allow private information to leak between private and normal browsing tabs. This could enable unauthorized access to protected information. The vulnerability is mitigated by the requirement for manual user input of the Blob URL to exploit the issue. Recommendations: For versions prior to 58, update to version 58 or later to resolve the issue. As a temporary workaround, consider avoiding manual entry of Blob URLs in private browsing tabs to minimize the risk of exploitation. Restrict access to sensitive information in private browsing tabs until the issue is resolved.