Mozilla Thunderbird is a standalone mail and newsgroup client. Security Fix(es): * firefox: thunderbird: Privilege escalation in the DOM: Workers component (CVE-2026-16365) * firefox: thunderbird: Sandbox escape in the Remote Settings Client component (CVE-2026-75874) * firefox: Sandbox escape due to use-after-free in the DOM: Security component (CVE-2026-84121) * firefox: Internally found bugs fixed in Firefox 155, Firefox ESR 153.2, Firefox ESR 140.15 and Firefox ESR 115.40 (CVE-2026-84145) * firefox: Sandbox escape due to use-after-free in the DOM: Navigation component (CVE-2026-84119) * firefox: Use-after-free in the Audio/Video component (CVE-2026-84120) * firefox: Privilege escalation due to invalid pointer in the Graphics component (CVE-2026-84131) * firefox: Use-after-free in the DOM: Core & HTML component (CVE-2026-84124) * firefox: Use-after-free in the Audio/Video component (CVE-2026-84122) * firefox: Internally found bugs fixed in Firefox 155, Firefox ESR 153.2 and Firefox ESR 140.15 (CVE-2026-84143) * thunderbird: Uninitialized memory in MIME parsing (CVE-2026-84639) * thunderbird: Information disclosure due to malicious IMAP server response (CVE-2026-84641) * thunderbird: One byte overflow read in mail parser (CVE-2026-84640) * firefox: thunderbird: Use-after-free in the SVG component (CVE-2026-92024) * firefox: thunderbird: Mitigation bypass in the Remote Settings Client component (CVE-2026-92019) * firefox: thunderbird: Use-after-free in the Networking component (CVE-2026-92026) * firefox: thunderbird: Information disclosure in the Graphics: ImageLib component (CVE-2026-92031) * firefox: thunderbird: Sandbox escape due to invalid pointer in the Graphics component (CVE-2026-92032) * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92010) * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92006) * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92011) * firefox: thunderbird: Use-after-free in the DOM: Streams component (CVE-2026-92027) * firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-92028) * firefox: thunderbird: Privilege escalation in the WebExtensions component (CVE-2026-92015) * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92013) * firefox: thunderbird: Use-after-free in the Disability Access APIs component (CVE-2026-92016) * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92012) * firefox: thunderbird: Use-after-free in the DOM: HTML Parser component (CVE-2026-92022) * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics component (CVE-2026-92014) * firefox: thunderbird: Sandbox escape in the DOM: Core & HTML component (CVE-2026-92018) * firefox: thunderbird: Use-after-free in the JavaScript Engine: JIT component (CVE-2026-92021) * firefox: thunderbird: Use-after-free in the Audio/Video: Web Codecs component (CVE-2026-92005) * firefox: thunderbird: Privilege escalation in the DOM: Service Workers component (CVE-2026-92017) * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92009) * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: WebRender component (CVE-2026-92020) * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92008) * firefox: thunderbird: Mitigation bypass in the DOM: Copy & Paste and Drag & Drop component (CVE-2026-92030) * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92007) * firefox: thunderbird: Use-after-free in the DOM: Navigation component (CVE-2026-92025) * firefox: thunderbird: Use-after-free in the SVG component (CVE-2026-92029) * firefox: thunderbird: Use-after-free in the XML component (CVE-2026-92023) * thunderbird: Out-of-bounds read in IMAP response parser (CVE-2026-92240) * thunderbird: Thunderbird: Out-of-bounds read via maliciously constructed IMAP line (CVE-2026-92239) * thunderbird: Thunderbird: Memory safety violations via maliciously crafted mail headers (CVE-2026-92238) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.