RHSA-2026:3978 — Security Advisory

An update for thunderbird is now available for Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions.

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):

• libvpx: Heap buffer overflow in libvpx (CVE-2026-2447)

• firefox: Invalid pointer in the JavaScript Engine component (CVE-2026-2785)

• firefox: Memory safety bugs fixed in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148 (CVE-2026-2793)

• firefox: Undefined behavior in the DOM: Core & HTML component (CVE-2026-2771)

• firefox: Integer overflow in the Audio/Video component (CVE-2026-2774)

• firefox: Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software (CVE-2026-2776)

• firefox: Integer overflow in the Libraries component in NSS (CVE-2026-2781)

• firefox: Use-after-free in the JavaScript Engine: JIT component (CVE-2026-2766)

• firefox: Use-after-free in the Storage: IndexedDB component (CVE-2026-2769)

• firefox: Use-after-free in the DOM: Window and Location component (CVE-2026-2787)

• firefox: Sandbox escape in the Storage: IndexedDB component (CVE-2026-2768)

• firefox: Information disclosure due to JIT miscompilation in the JavaScript Engine: JIT component (CVE-2026-2783)

• firefox: Incorrect boundary conditions in the Audio/Video: GMP component (CVE-2026-2788)

• firefox: Mitigation bypass in the DOM: Security component (CVE-2026-2784)

• firefox: Incorrect boundary conditions in the Graphics: ImageLib component (CVE-2026-2759)

• firefox: Integer overflow in the JavaScript: Standard Library component (CVE-2026-2762)

• firefox: Sandbox escape in the Graphics: WebRender component (CVE-2026-2761)

• firefox: Privilege escalation in the Messaging System component (CVE-2026-2777)

• firefox: Same-origin policy bypass in the Networking: JAR component (CVE-2026-2790)

• firefox: Mitigation bypass in the DOM: HTML Parser component (CVE-2026-2775)

• firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2763)

• firefox: Memory safety bugs fixed in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148 (CVE-2026-2792)

• firefox: Incorrect boundary conditions in the Web Audio component (CVE-2026-2773)

• firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2786)

• firefox: Use-after-free in the Graphics: ImageLib component (CVE-2026-2789)

• firefox: thunderbird: Incorrect boundary conditions in the WebRTC: Audio/Video component (CVE-2026-2757)

• firefox: Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component (CVE-2026-2760)

• firefox: Use-after-free in the Audio/Video: Playback component (CVE-2026-2772)

• firefox: Incorrect boundary conditions in the Networking: JAR component (CVE-2026-2779)

• firefox: Use-after-free in the JavaScript: WebAssembly component (CVE-2026-2767)

• firefox: JIT miscompilation, use-after-free in the JavaScript Engine: JIT component (CVE-2026-2764)

• firefox: Privilege escalation in the Netmonitor component (CVE-2026-2782)

• firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2765)

• firefox: Privilege escalation in the Netmonitor component (CVE-2026-2780)

• firefox: Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component (CVE-2026-2778)

• firefox: Use-after-free in the JavaScript: GC component (CVE-2026-2758)

• firefox: Mitigation bypass in the Networking: Cache component (CVE-2026-2791)

• firefox: Use-after-free in the DOM: Bindings (WebIDL) component (CVE-2026-2770)

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.