Mozilla Thunderbird vulnerabilities

CVE-2026-8948 [CRITICAL] CWE-942 CVE-2026-8948: Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

CVE-2026-8959 [CRITICAL] CWE-20 CVE-2026-8959: Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerabili Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVE-2026-8950 [CRITICAL] CWE-346 CVE-2026-8950: Same-origin policy bypass in the Networking: HTTP component. This vulnerability was fixed in Firefox Same-origin policy bypass in the Networking: HTTP component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVE-2026-8953 [CRITICAL] CWE-416 CVE-2026-8953: Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVE-2026-8956 [CRITICAL] CWE-190 CVE-2026-8956: Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151, Fire Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVE-2026-8970 [HIGH] CWE-269 CVE-2026-8970: Privilege escalation in the Security component. This vulnerability was fixed in Firefox 151, Firefox Privilege escalation in the Security component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVE-2026-8965 [HIGH] CWE-200 CVE-2026-8965: Information disclosure in the DOM: Security component. This vulnerability was fixed in Firefox 151 a Information disclosure in the DOM: Security component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

CVE-2026-8974 [HIGH] CWE-119 CVE-2026-8974: Memory safety bugs present in Firefox ESR 140.10 and Firefox 150. Some of these bugs showed evidence Memory safety bugs present in Firefox ESR 140.10 and Firefox 150. 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. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVE-2026-8954 [HIGH] CWE-119 CVE-2026-8954: Incorrect boundary conditions, integer overflow in the Audio/Video component. This vulnerability was Incorrect boundary conditions, integer overflow in the Audio/Video component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVE-2026-8967 [HIGH] CWE-200 CVE-2026-8967: Information disclosure in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 15 Information disclosure in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

CVE-2026-8966 [HIGH] CWE-200 CVE-2026-8966: Information disclosure in the IP Protection component. This vulnerability was fixed in Firefox 151 a Information disclosure in the IP Protection component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

CVE-2026-8962 [HIGH] CWE-693 CVE-2026-8962: Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151, Firef Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVE-2026-8969 [HIGH] CWE-693 CVE-2026-8969: Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151 and Th Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

CVE-2026-8972 [HIGH] CWE-269 CVE-2026-8972: Privilege escalation in the WebRTC: Audio/Video component. This vulnerability was fixed in Firefox 1 Privilege escalation in the WebRTC: Audio/Video component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

CVE-2026-8964 [HIGH] CWE-451 CVE-2026-8964: Spoofing issue in the Popup Blocker component. This vulnerability was fixed in Firefox 151 and Thund Spoofing issue in the Popup Blocker component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

CVE-2026-8968 [HIGH] CWE-400 CVE-2026-8968: Denial-of-service due to invalid pointer in the Audio/Video: Web Codecs component. This vulnerabilit Denial-of-service due to invalid pointer in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVE-2026-8958 [HIGH] CWE-668 CVE-2026-8958: Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerabi Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVE-2026-8949 [HIGH] CWE-190 CVE-2026-8949: Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefo Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVE-2026-8973 [HIGH] CWE-119 CVE-2026-8973: Memory safety bugs present in Firefox 150. Some of these bugs showed evidence of memory corruption a Memory safety bugs present in Firefox 150. 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. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

CVE-2026-8960 [HIGH] CWE-290 CVE-2026-8960: Spoofing issue in WebExtensions. This vulnerability was fixed in Firefox 151 and Thunderbird 151. Spoofing issue in WebExtensions. This vulnerability was fixed in Firefox 151 and Thunderbird 151.