Security Vulnerabilities fixed in Thunderbird 153 — Mozilla

The code to parse MIME headers for display when forwarding a message if the setting to view all headers was enabled had an off-by-one error, allowing a single byte to be read from the memory after the buffer for the headers, and potentially crashing Thunderbird. Memory safety bugs present in...

PT-2026-61883

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: Navigation component. Recommendations...

PT-2026-61886

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 An information disclosure issue exists within the Framework component of DevTools...

PT-2026-61893

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 same-origin policy bypass exists in the Networking: DNS component. The same-origin policy i...

PT-2026-61895

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 DOM: Networking component. Recommendations Update Firef...

PT-2026-61903

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 An information disclosure issue exists within the Storage: IndexedDB component. IndexedDB is ...

PT-2026-61874

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 use-after-free issue exists in the WebRTC: Audio/Video component. Use-after-free is a memor...

PT-2026-61875

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 JIT miscompilation issue exists within the JavaScript: WebAssembly component. JIT...

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...

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-2026-61905

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Thunderbird versions prior to 153 Description Incorrect boundary conditions exist within the Graphics: WebGPU component. WebGPU is a modern API that allows web applications to access the GPU for hardware-accelerat...

PT-2026-61904

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Thunderbird versions prior to 153 Description A JIT miscompilation issue exists within the JIT component of the JavaScript Engine. JIT Just-In-Time compilation is a method used by the engine to improve performance...

PT-2026-61885

Name of the Vulnerable Software and Affected Versions Firefox for Android versions prior to 153 Description An information disclosure issue exists within the Privacy component, which could allow sensitive data to be exposed. Recommendations Update to version 153...

PT-2026-61890

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Thunderbird versions prior to 153 Description An issue exists in the Document Object Model DOM specifically within the Copy & Paste and Drag & Drop component. Recommendations Update Firefox to version 153. Update...

PT-2026-61876

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Thunderbird versions prior to 153 Description Incorrect boundary conditions exist within the Audio/Video: Playback component. Recommendations Update Firefox to version 153. Update Thunderbird to version 153...

PT-2026-61920

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Thunderbird versions prior to 153 Description An integer overflow exists within the Audio/Video: Playback component. An integer overflow occurs when an arithmetic operation attempts to create a numeric value that ...

PT-2026-61894

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Thunderbird versions prior to 153 Description A mitigation bypass exists within the DOM: Service Workers component. Service Workers are scripts that the browser runs in the background, separate from a web page,...

PT-2026-61919

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Thunderbird versions prior to 153 Description A mitigation bypass exists within the DOM: Service Workers component. Service Workers are scripts that the browser runs in the background, separate from a web page,...

PT-2026-61923

Name of the Vulnerable Software and Affected Versions Firefox version 152 Thunderbird version 152 Description Memory safety bugs were identified that showed evidence of memory corruption. These issues could potentially be exploited to execute arbitrary code. Recommendations Update Firefox to...

PT-2026-61907

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Thunderbird versions prior to 153 Description An integer overflow exists within the Audio/Video component. An integer overflow occurs when an arithmetic operation attempts to create a numeric value that is outside...