Carl Smith

**Name of the Vulnerable Software and Affected Versions** Firefox versions prior to 79 Firefox ESR versions prior to 78.1 Thunderbird versions prior to 78.1 **Description** The issue is related to JIT-optimization in the browser, which can allow unauthorized access to data due to a lack of type control. This could potentially enable a remote attacker to access confidential data, compromise its integrity, and cause a denial of service. The vulnerability involves JIT optimizations with the Javascript arguments object, which could confuse later optimizations, although various precautions in the code mitigate this risk. **Recommendations** For Firefox versions prior to 79, update to version 79 or later to resolve the issue. For Firefox ESR versions prior to 78.1, update to version 78.1 or later to resolve the issue. For Thunderbird versions prior to 78.1, update to version 78.1 or later to resolve the issue.