Security Vulnerabilities fixed in Firefox 153 — Mozilla

Memory safety bugs present in Firefox 152. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. Memory safety bugs present in Firefox ESR 140.12 and Firefox 152. Some of these bugs showed...

PT-2026-61861

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Firefox ESR versions prior to 115.38 Firefox ESR versions prior to 140.13 Thunderbird versions prior to 153 Thunderbird version prior to 140.13 Description A same-origin policy bypass exists in the DOM Navigation...

PT-2026-61862

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Firefox ESR versions prior to 115.38 Firefox ESR versions prior to 140.13 Thunderbird versions prior to 153 Thunderbird version prior to 140.13 Description Incorrect boundary conditions exist within the Audio/Vide...

PT-2026-61872

Name of the Vulnerable Software and Affected Versions Firefox ESR version 115.37 Firefox ESR version 140.12 Firefox version 152 Thunderbird ESR version 140.12 Thunderbird version 152 Description Memory safety bugs were identified that showed evidence of memory corruption. These issues could...

PT-2026-61889

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Firefox ESR versions prior to 140.13 Thunderbird versions prior to 153 Thunderbird versions prior to 140.13 Description A mitigation bypass exists within the PDF Viewer component. Recommendations Update Firefox to...

PT-2026-61891

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Firefox ESR versions prior to 140.13 Thunderbird versions prior to 153 Thunderbird versions prior to 140.13 Description A privilege escalation issue exists within the DOM: Content Processes component...

PT-2026-61902

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Firefox ESR versions prior to 140.13 Thunderbird versions prior to 153 Thunderbird versions prior to 140.13 Description A mitigation bypass exists within the Enterprise Policies component. Recommendations Update...

PT-2026-61898

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Thunderbird versions prior to 153 Description An information disclosure issue exists in the Graphics: WebGPU component caused by uninitialized memory. This occurs when the system fails to clear a memory area befor...

PT-2026-61911

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Thunderbird versions prior to 153 Description A site isolation issue exists within the DOM Navigation component. Site isolation is a security mechanism that ensures web pages from different sites are processed in...

PT-2026-61909

Name of the Vulnerable Software and Affected Versions Firefox for Android versions prior to 153 Description A clickjacking issue exists in the WebExtensions component. Clickjacking is a technique where an attacker uses multiple transparent or semi-transparent layers to trick a user into clicking ...

PT-2026-61878

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Thunderbird versions prior to 153 Description A privilege escalation issue exists within the DOM Navigation component. Recommendations Update Firefox to version 153. Update Thunderbird to version 153...

PT-2026-61866

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Firefox ESR versions prior to 115.38 Firefox ESR versions prior to 140.13 Thunderbird versions prior to 153 Thunderbird version prior to 140.13 Description An information disclosure issue exists within the Graphic...

PT-2026-61871

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Firefox ESR versions prior to 115.38 Firefox ESR versions prior to 140.13 Thunderbird versions prior to 153 Thunderbird version prior to 140.13 Description Incorrect boundary conditions exist within the Audio/Vide...