OESA-2026-1285

Mozilla Thunderbird is a standalone mail and newsgroup client.

Security Fix(es):

Use-after-free in the WebRTC: Signaling component. This vulnerability affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.(CVE-2025-14321)

Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability affects Firefox < 146, Firefox ESR < 115.31, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.(CVE-2025-14322)

JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability affects Firefox < 146, Firefox ESR < 115.31, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.(CVE-2025-14324)

JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.(CVE-2025-14325)

Spoofing issue in the Downloads Panel component. This vulnerability affects Firefox < 146, Thunderbird < 146, Firefox ESR < 140.7, and Thunderbird < 140.7.(CVE-2025-14327)

Privilege escalation in the Netmonitor component. This vulnerability affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.(CVE-2025-14328)

Privilege escalation in the Netmonitor component. This vulnerability affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.(CVE-2025-14329)

JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.(CVE-2025-14330)

Same-origin policy bypass in the Request Handling component. This vulnerability affects Firefox < 146, Firefox ESR < 115.31, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.(CVE-2025-14331)

Memory safety bugs present in Firefox ESR 140.5, Thunderbird ESR 140.5, Firefox 145 and Thunderbird 145. 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 affects Firefox < 146, Firefox ESR < 140.6, Thunderbird < 146, and Thunderbird < 140.6.(CVE-2025-14333)

A mitigation bypass vulnerability exists in the DOM (Document Object Model) security component of Mozilla Firefox. This vulnerability could allow an attacker to bypass security mitigations, potentially leading to remote code execution, impacting the confidentiality, integrity, and availability of the system. This vulnerability affects Firefox versions < 147, Firefox ESR versions < 115.32, and Firefox ESR versions < 140.7.(CVE-2026-0877)

Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.(CVE-2026-0878)

Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability affects Firefox < 147, Firefox ESR < 115.32, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.(CVE-2026-0879)

Sandbox escape due to integer overflow in the Graphics component. This vulnerability affects Firefox < 147, Firefox ESR < 115.32, and Firefox ESR < 140.7.(CVE-2026-0880)

A use-after-free vulnerability exists in the Inter-Process Communication (IPC) component of Mozilla Firefox. An attacker could potentially exploit this vulnerability to access or manipulate memory regions after they have been freed, leading to program crashes, arbitrary code execution, or information disclosure. This vulnerability poses a threat to confidentiality, integrity, and availability.(CVE-2026-0882)

An information disclosure vulnerability (CWE-200) exists in the Networking component of Mozilla Firefox. This vulnerability allows an unauthorized actor to access sensitive information, primarily impacting confidentiality. It affects all versions of Firefox prior to version 147 (i.e., Firefox < 147) and all versions of Firefox ESR prior to version 140.7 (i.e., Firefox ESR < 140.7).(CVE-2026-0883)

Use-after-free in the JavaScript Engine component. This vulnerability affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.(CVE-2026-0884)

Use-after-free in the JavaScript: GC component. This vulnerability affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.(CVE-2026-0885)

Incorrect boundary conditions in the Graphics component. This vulnerability affects Firefox < 147, Firefox ESR < 115.32, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.(CVE-2026-0886)

A clickjacking vulnerability exists in the built-in PDF Viewer component of Mozilla Firefox, which could lead to information disclosure. The vulnerability stems from the web application's failure to properly restrict frame objects or UI layers belonging to another application or domain, potentially causing user confusion about which interface they are interacting with, impacting integrity. This vulnerability affects Firefox versions prior to 147 and Firefox ESR versions prior to 140.7.(CVE-2026-0887)

A spoofing vulnerability exists in the DOM Copy & Paste and Drag & Drop component of Mozilla Firefox. The vulnerability stems from the web application's failure to properly restrict frame objects or UI layers belonging to other applications or domains, which can lead to user confusion about which interface they are interacting with, thereby compromising data integrity. This vulnerability affects Firefox versions prior to 147 and Firefox ESR versions prior to 140.7.(CVE-2026-0890)

Multiple memory safety bugs were present in Mozilla Firefox ESR 140.6, Thunderbird ESR 140.6, Firefox 146, and Thunderbird 146. Some of these bugs showed evidence of memory corruption, and it is presumed that with enough effort, some could have been exploited to run arbitrary code. This vulnerability affects Firefox < 147 and Firefox ESR < 140.7, threatening confidentiality, integrity, and availability.(CVE-2026-0891)