Mozilla Thunderbird vulnerabilities

CVE-2026-2790 [CRITICAL] CWE-346 CVE-2026-2790: Same-origin policy bypass in the Networking: JAR component. This vulnerability was fixed in Firefox Same-origin policy bypass in the Networking: JAR component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CVE-2026-2800 [CRITICAL] CWE-290 CVE-2026-2800: Spoofing issue in the WebAuthn component in Firefox for Android. This vulnerability was fixed in Fir Spoofing issue in the WebAuthn component in Firefox for Android. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

CVE-2026-2765 [CRITICAL] CWE-416 CVE-2026-2765: Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 148, Fire Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CVE-2026-2787 [CRITICAL] CWE-416 CVE-2026-2787: Use-after-free in the DOM: Window and Location component. This vulnerability was fixed in Firefox 14 Use-after-free in the DOM: Window and Location component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CVE-2026-2760 [CRITICAL] CWE-1384 CVE-2026-2760: Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component. This vulne Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CVE-2026-2758 [CRITICAL] CWE-416 CVE-2026-2758: Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 148, Firefox Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CVE-2026-2797 [CRITICAL] CWE-416 CVE-2026-2797: Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 148 and Thun Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

CVE-2026-2769 [HIGH] CWE-416 CVE-2026-2769: Use-after-free in the Storage: IndexedDB component. This vulnerability was fixed in Firefox 148, Fir Use-after-free in the Storage: IndexedDB component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CVE-2026-2783 [HIGH] CWE-843 CVE-2026-2783: Information disclosure due to JIT miscompilation in the JavaScript Engine: JIT component. This vulne Information disclosure due to JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CVE-2026-2803 [HIGH] CWE-200 CVE-2026-2803: Information disclosure, mitigation bypass in the Settings UI component. This vulnerability was fixed Information disclosure, mitigation bypass in the Settings UI component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

CVE-2026-2801 [HIGH] CWE-754 CVE-2026-2801: Incorrect boundary conditions in the JavaScript: WebAssembly component. This vulnerability was fixed Incorrect boundary conditions in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

CVE-2026-2798 [HIGH] CWE-416 CVE-2026-2798: Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148 and Th Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

CVE-2026-2804 [MEDIUM] CWE-416 CVE-2026-2804: Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

CVE-2026-2802 [MEDIUM] CWE-362 CVE-2026-2802: Race condition in the JavaScript: GC component. This vulnerability was fixed in Firefox 148 and Thun Race condition in the JavaScript: GC component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

CVE-2026-2447 [HIGH] CWE-122 CVE-2026-2447: Heap buffer overflow in libvpx. This vulnerability was fixed in Firefox 147.0.4, Firefox ESR 140.7.1 Heap buffer overflow in libvpx. This vulnerability was fixed in Firefox 147.0.4, Firefox ESR 140.7.1, Firefox ESR 115.32.1, Thunderbird 140.7.2, and Thunderbird 147.0.2.

CVE-2026-0818 [MEDIUM] CWE-116 CVE-2026-0818: When a user explicitly requested Thunderbird to decrypt an inline OpenPGP message that was embedded When a user explicitly requested Thunderbird to decrypt an inline OpenPGP message that was embedded in a text section of an email that was formatted and styled with HTML and CSS, then the decrypted contents were rendered in a context in which the CSS styles from the outer messages were active. If the user had additionally allowed loading of the remote

CVE-2026-0879 [CRITICAL] CWE-119 CVE-2026-0879: Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability wa Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox 147, Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

CVE-2026-0892 [CRITICAL] CWE-119 CVE-2026-0892: Memory safety bugs present in Firefox 146 and Thunderbird 146. Some of these bugs showed evidence of Memory safety bugs present in Firefox 146 and Thunderbird 146. 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 147 and Thunderbird 147.

CVE-2026-0884 [CRITICAL] CWE-416 CVE-2026-0884: Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 147, Fire Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

CVE-2026-0881 [CRITICAL] CWE-284 CVE-2026-0881: Sandbox escape in the Messaging System component. This vulnerability was fixed in Firefox 147 and Th Sandbox escape in the Messaging System component. This vulnerability was fixed in Firefox 147 and Thunderbird 147.