RHSA-2026:54339 — Security Advisory

An update for firefox is now available for Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions and Red Hat Enterprise Linux 8.8 Telecommunications Update Service.

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 Firefox is an open-source web browser, designed for standards compliance, performance, and portability.

Security Fix(es):

• libaom: libaom: heap buffer overflow in AV1 encoder first-pass stats buffer via LAP mode (CVE-2026-56208)

• firefox: thunderbird: Site isolation issue in the DOM: Navigation component (CVE-2026-15719)

• firefox: thunderbird: Invalid pointer in the JavaScript: WebAssembly component (CVE-2026-15718)

• firefox: thunderbird: Mitigation bypass in the Enterprise Policies component (CVE-2026-16390)

• firefox: thunderbird: Incorrect boundary conditions in the Audio/Video: cubeb component (CVE-2026-16350)

• firefox: thunderbird: Information disclosure in the Storage: IndexedDB component (CVE-2026-16391)

• firefox: thunderbird: Site isolation issue in the Networking: HTTP component (CVE-2026-16375)

• firefox: thunderbird: Sandbox escape due to use-after-free in the Disability Access APIs component (CVE-2026-16356)

• firefox: thunderbird: JIT miscompilation in the JavaScript: WebAssembly component (CVE-2026-16363)

• firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 140.13 and Firefox 153 (CVE-2026-16412)

• firefox: thunderbird: Same-origin policy bypass in the Networking: DNS component (CVE-2026-16381)

• firefox: thunderbird: JIT miscompilation in the JavaScript Engine: JIT component (CVE-2026-16355)

• firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.38 and Firefox ESR 140.13 (CVE-2026-16361)

• firefox: thunderbird: Sandbox escape due to use-after-free in the Disability Access APIs component (CVE-2026-16352)

• firefox: thunderbird: Incorrect boundary conditions in the JavaScript: WebAssembly component (CVE-2026-16368)

• firefox: thunderbird: Mitigation bypass in the PDF Viewer component (CVE-2026-16377)

• firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.38, Firefox ESR 140.13 and Firefox 153 (CVE-2026-16360)

• firefox: thunderbird: Use-after-free in the WebRTC: Audio/Video component (CVE-2026-16362)

• firefox: thunderbird: Site isolation issue in the Graphics: WebRender component (CVE-2026-16358)

• firefox: thunderbird: Site isolation issue in the Networking component (CVE-2026-16387)

• firefox: thunderbird: Same-origin policy bypass in the DOM: Navigation component (CVE-2026-16349)

• firefox: thunderbird: Incorrect boundary conditions in the Graphics component (CVE-2026-16357)

• firefox: thunderbird: Sandbox escape due to use-after-free in the DOM: Navigation component (CVE-2026-16351)

• firefox: thunderbird: Privilege escalation in the DOM: Navigation component (CVE-2026-16371)

• firefox: thunderbird: Privilege escalation in the DOM: Content Processes component (CVE-2026-16379)

• firefox: thunderbird: Information disclosure in the Graphics: ImageLib component (CVE-2026-16354)

• firefox: thunderbird: Information disclosure in the Framework component in DevTools (CVE-2026-16374)

• firefox: thunderbird: Incorrect boundary conditions in the Audio/Video: GMP component (CVE-2026-16359)

• firefox: thunderbird: Mitigation bypass in the DOM: Networking component (CVE-2026-16383)

• firefox: thunderbird: Integer overflow in the JavaScript: WebAssembly component (CVE-2026-16369)

• firefox: thunderbird: Invalid pointer in the DOM: Bindings (WebIDL) component (CVE-2026-16353)

• firefox: thunderbird: Privilege escalation in WebExtensions (CVE-2026-16396)

• firefox: thunderbird: Information disclosure in the Networking: WebSockets component (CVE-2026-16405)

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.