RHSA-2026:19201 — Security Advisory

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

Security Fix(es):

• firefox: thunderbird: Incorrect boundary conditions in the Libraries component in NSS (CVE-2026-6772)

• firefox: thunderbird: Use-after-free in the JavaScript Engine component (CVE-2026-6754)

• firefox: thunderbird: Spoofing issue in the DOM: Core & HTML component (CVE-2026-6762)

• firefox: thunderbird: Incorrect boundary conditions in the WebRTC component (CVE-2026-6752)

• firefox: thunderbird: Other issue in the Storage: IndexedDB component (CVE-2026-6770)

• firefox: thunderbird: Invalid pointer in the JavaScript: WebAssembly component (CVE-2026-6757)

• firefox: thunderbird: Other issue in the Libraries component in NSS (CVE-2026-6767)

• firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150 (CVE-2026-6786)

• firefox: thunderbird: Incorrect boundary conditions in the WebRTC component (CVE-2026-6753)

• firefox: thunderbird: Use-after-free in the Widget: Cocoa component (CVE-2026-6759)

• firefox: thunderbird: Use-after-free in the WebRTC component (CVE-2026-6747)

• firefox: thunderbird: Information disclosure due to uninitialized memory in the Graphics: Canvas2D component (CVE-2026-6749)

• firefox: thunderbird: Incorrect boundary conditions in the Libraries component in NSS (CVE-2026-6766)

• firefox: thunderbird: Privilege escalation in the Networking component (CVE-2026-6761)

• firefox: thunderbird: Mitigation bypass in the File Handling component (CVE-2026-6763)

• firefox: thunderbird: Privilege escalation in the Graphics: WebRender component (CVE-2026-6750)

• firefox: thunderbird: Uninitialized memory in the Audio/Video: Web Codecs component (CVE-2026-6748)

• firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150 (CVE-2026-6785)

• firefox: thunderbird: Mitigation bypass in the DOM: Security component (CVE-2026-6771)

• firefox: thunderbird: Incorrect boundary conditions in the DOM: Device Interfaces component (CVE-2026-6764)

• firefox: thunderbird: Information disclosure in the Form Autofill component (CVE-2026-6765)

• firefox: thunderbird: Privilege escalation in the Debugger component (CVE-2026-6769)

• firefox: thunderbird: Uninitialized memory in the Audio/Video: Web Codecs component (CVE-2026-6751)

• firefox: thunderbird: Incorrect boundary conditions in the WebRTC: Networking component (CVE-2026-6776)

• firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-6746)

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.