RHSA-2026:80694 — Security Advisory

An update for thunderbird is now available for Red Hat Enterprise Linux 9.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Mozilla Thunderbird is a standalone mail and newsgroup client.

Security Fix(es):

• firefox: thunderbird: Use-after-free in the Graphics: Canvas2D component (CVE-2026-100832)

• firefox: Use-after-free in the Layout: Text and Fonts component (CVE-2026-100784)

• firefox: thunderbird: Privilege escalation in the DLL Services component (CVE-2026-100801)

• firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Internationalization component (CVE-2026-100794)

• firefox: thunderbird: Privilege escalation in the Address Bar component (CVE-2026-100820)

• firefox: thunderbird: Use-after-free in the Graphics: Canvas2D component (CVE-2026-100777)

• firefox: thunderbird: Information disclosure in the Networking: JAR component (CVE-2026-100766)

• firefox: thunderbird: Use-after-free in the XSLT component (CVE-2026-100779)

• firefox: thunderbird: Privilege escalation in the DOM: Service Workers component (CVE-2026-100807)

• firefox: thunderbird: JIT miscompilation in the JavaScript: WebAssembly component (CVE-2026-100792)

• firefox: Privilege escalation due to use-after-free in the Graphics: WebRender component (CVE-2026-100797)

• firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the XPCOM component (CVE-2026-100819)

• firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component (CVE-2026-100776)

• firefox: thunderbird: Use-after-free in the Widget component (CVE-2026-100757)

• firefox: Sandbox escape due to use-after-free in the Graphics component (CVE-2026-100786)

• firefox: thunderbird: Information disclosure in the Networking component (CVE-2026-96869)

• firefox: Sandbox escape due to use-after-free in the DOM: Content Processes component (CVE-2026-100770)

• firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component (CVE-2026-100769)

• firefox: Use-after-free in the DOM: Core & HTML component (CVE-2026-100791)

• firefox: thunderbird: Sandbox escape due to use-after-free in the Widget: Gtk component (CVE-2026-100818)

• firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics component (CVE-2026-100782)

• firefox: firefox: Sandbox escape via use-after-free in DOM component (CVE-2026-100811)

• firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-100772)

• firefox: thunderbird: Uninitialized memory in the Storage: Quota Manager component (CVE-2026-100759)

• firefox: Sandbox escape due to use-after-free in the DOM: Core & HTML component (CVE-2026-100778)

• firefox: thunderbird: Sandbox escape in the DOM: Navigation component (CVE-2026-100758)

• firefox: thunderbird: Sandbox escape in the Graphics component (CVE-2026-100775)

• firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component (CVE-2026-100781)

• firefox: Use-after-free in the DOM: Core & HTML component (CVE-2026-100774)

• firefox: thunderbird: Same-origin policy bypass in the WebExtensions component (CVE-2026-100803)

• firefox: thunderbird: Use-after-free in the Graphics: Canvas2D component (CVE-2026-100789)

• firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-100785)

• firefox: thunderbird: Site isolation issue in the Panning and Zooming component (CVE-2026-100821)

• firefox: thunderbird: Invalid pointer in the JavaScript: WebAssembly component (CVE-2026-100788)

• firefox: thunderbird: Undefined behavior in the DOM: Streams component (CVE-2026-100771)

• firefox: Sandbox escape due to use-after-free in the DOM: Content Processes component (CVE-2026-100762)

• firefox: thunderbird: Use-after-free in the XSLT component (CVE-2026-100790)

• firefox: thunderbird: Use-after-free in the Storage: IndexedDB component (CVE-2026-100773)

• firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-100780)

• firefox: thunderbird: Use-after-free in the Networking: Cache component (CVE-2026-100767)

• firefox: thunderbird: Incorrect boundary conditions in the Audio/Video: Playback component (CVE-2026-100756)

• firefox: thunderbird: Uninitialized memory in the Audio/Video component (CVE-2026-100783)

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.