Mozilla Firefox vulnerabilities

CVE-2026-2771 [CRITICAL] CWE-125 CVE-2026-2771: Undefined behavior in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148, F Undefined behavior in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CVE-2026-74990 [CRITICAL] CWE-119 CVE-2026-74990: Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 1

CVE-2026-74987 [CRITICAL] CWE-119 CVE-2026-74987: Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 1

CVE-2026-16389 [CRITICAL] CWE-190 CVE-2026-16389: Incorrect boundary conditions, integer overflow in the Libraries component in NSS. This vulnerabilit Incorrect boundary conditions, integer overflow in the Libraries component in NSS. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CVE-2026-16402 [CRITICAL] CWE-190 CVE-2026-16402: Integer overflow in the Graphics: ImageLib component. This vulnerability was fixed in Firefox 153 an Integer overflow in the Graphics: ImageLib component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CVE-2026-74988 [CRITICAL] CWE-119 CVE-2026-74988: Internally found bugs present in Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showe Internally found bugs present in Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.

CVE-2026-2757 [CRITICAL] CWE-1384 CVE-2026-2757: Incorrect boundary conditions in the WebRTC: Audio/Video component. This vulnerability was fixed in Incorrect boundary conditions in the WebRTC: Audio/Video component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CVE-2026-2785 [CRITICAL] CWE-824 CVE-2026-2785: Invalid pointer in the JavaScript Engine component. This vulnerability was fixed in Firefox 148, Fir Invalid pointer in the JavaScript Engine component. This vulnerability was fixed in Firefox 148, 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-2026-16411 [CRITICAL] CWE-119 CVE-2026-16411: Memory safety bugs present in Thunderbird 152. Some of these bugs showed evidence of memory corrupti Memory safety bugs present in Thunderbird 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. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CVE-2026-92036 [CRITICAL] CWE-119 CVE-2026-92036: Incorrect boundary conditions in the Networking: HTTP component. This vulnerability was fixed in Fir Incorrect boundary conditions in the Networking: HTTP component. This vulnerability was fixed in Firefox 156 and Thunderbird 156.

CVE-2026-16388 [CRITICAL] CWE-693 CVE-2026-16388: Sandbox escape in the DOM: Networking component. This vulnerability was fixed in Firefox 153 and Thu Sandbox escape in the DOM: Networking component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CVE-2024-9392 [CRITICAL] CWE-346 CVE-2024-9392: A compromised content process could have allowed for the arbitrary loading of cross-origin pages. Th A compromised content process could have allowed for the arbitrary loading of cross-origin pages. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Firefox ESR < 115.16, Thunderbird < 128.3, and Thunderbird < 131.

CVE-2025-8031 [CRITICAL] CWE-276 CVE-2025-8031: The `username:password` part was not correctly stripped from URLs in CSP reports potentially leaking The `username:password` part was not correctly stripped from URLs in CSP reports potentially leaking HTTP Basic Authentication credentials. This vulnerability was fixed in Firefox 141, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.

CVE-2026-4691 [CRITICAL] CWE-416 CVE-2026-4691: Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-2759 [CRITICAL] CWE-1384 CVE-2026-2759: Incorrect boundary conditions in the Graphics: ImageLib component. This vulnerability was fixed in F Incorrect boundary conditions in the Graphics: ImageLib component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CVE-2026-8091 [CRITICAL] CWE-754 CVE-2026-8091: Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed i Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 150, Thunderbird 150, Firefox ESR 140.10.1, Thunderbird 140.10.1, and Firefox ESR 115.35.2.

CVE-2026-8094 [CRITICAL] CWE-94 CVE-2026-8094: Other issue in the WebRTC component. This vulnerability was fixed in Firefox ESR 140.10.2 and Thunde Other issue in the WebRTC component. This vulnerability was fixed in Firefox ESR 140.10.2 and Thunderbird 140.10.2.

CVE-2026-4721 [CRITICAL] CWE-120 CVE-2026-4721: Memory safety bugs present in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox Memory safety bugs present in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148. 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 149, Firefox ESR 115.34, Fire

CVE-2025-55031 [CRITICAL] CWE-601 CVE-2025-55031: Malicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passk Malicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passkey transport. An attacker within Bluetooth range could have used this to trick the user into using their passkey to log the attacker's computer into the target account. This vulnerability was fixed in Firefox for iOS 142 and Focus for iOS 142.