RHSA-2026:58897: Important: firefox security update
Important: firefox security update
Other sources
Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and portability.Security Fix(es): firefox: thunderbird: Mitigation bypass in the Data Loss Prevention component (CVE-2026-74983) firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component (CVE-2026-74934) firefox: thunderbird: Privilege escalation in the Networking: Cookies component (CVE-2026-74953) firefox: thunderbird: Internally found bugs fixed in Firefox ESR 140.14, Firefox ESR 153.1 and Firefox 154 (CVE-2026-74987) firefox: thunderbird: Information disclosure in the Graphics component (CVE-2026-74948) firefox: thunderbird: Use-after-free in the Graphics: ImageLib component (CVE-2026-74943) firefox: thunderbird: Information disclosure in the DOM: UI Events & Focus Handling component (CVE-2026-74971) firefox: thunderbird: Privilege escalation in the Graphics: CanvasWebGL component (CVE-2026-74941) firefox: Privilege escalation in the Shell Integration component (CVE-2026-74965) firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-74946) firefox: Race condition, use-after-free in the Graphics component (CVE-2026-74973) firefox: thunderbird: Privilege escalation due to use-after-free in the Graphics: Canvas2D component (CVE-2026-74949) firefox: thunderbird: Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1 and Firefox 154 (CVE-2026-74990) firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component (CVE-2026-74936) firefox: thunderbird: Use-after-free in the Graphics: Text component (CVE-2026-74940) firefox: thunderbird: Site isolation issue in the WebExtensions component (CVE-2026-74960) firefox: thunderbird: Use-after-free in the Layout: Text and Fonts component (CVE-2026-74969) firefox: thunderbird: Mitigation bypass in the Storage: Cache API component (CVE-2026-74959) firefox: thunderbird: JIT miscompilation in the JavaScript Engine: JIT component (CVE-2026-74976) firefox: thunderbird: Same-origin policy bypass in the Graphics: ImageLib component (CVE-2026-74974) firefox: thunderbird: Mitigation bypass in the Safe Browsing component (CVE-2026-74957) firefox: thunderbird: Same-origin policy bypass in the Audio/Video: Playback component (CVE-2026-74967) firefox: Privilege escalation in the Remote Settings Client component (CVE-2026-74942) firefox: thunderbird: Privilege escalation in the DOM: Navigation component (CVE-2026-74939) firefox: thunderbird: Information disclosure in the DOM: Push Subscriptions component (CVE-2026-74972) firefox: thunderbird: Information disclosure in the Graphics: Text component (CVE-2026-74945) firefox: thunderbird: Same-origin policy bypass in the Networking: Cookies component (CVE-2026-74963) firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-74944) firefox: Integer overflow in the Graphics component (CVE-2026-74964) firefox: Site isolation issue in the Networking: Cookies component (CVE-2026-74962) firefox: thunderbird: Privilege escalation in the DOM: Networking component (CVE-2026-74935) 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.
— Red Hat
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/firefoxto a version that resolves this vulnerability.Fixed in 140.14.0-1.el9_8 - Upgrade
Upgrade
redhat/firefox-debuginfoto a version that resolves this vulnerability.Fixed in 140.14.0-1.el9_8 - Upgrade
Upgrade
redhat/firefox-debugsourceto a version that resolves this vulnerability.Fixed in 140.14.0-1.el9_8 - Upgrade
Upgrade
redhat/firefox-x11to a version that resolves this vulnerability.Fixed in 140.14.0-1.el9_8 - Upgrade
Upgrade
redhat/firefoxto a version that resolves this vulnerability.Fixed in 140.14.0-1.el9_8.aa - Upgrade
Upgrade
redhat/firefox-debuginfoto a version that resolves this vulnerability.Fixed in 140.14.0-1.el9_8.aa - Upgrade
Upgrade
redhat/firefox-debugsourceto a version that resolves this vulnerability.Fixed in 140.14.0-1.el9_8.aa - Upgrade
Upgrade
redhat/firefox-x11to a version that resolves this vulnerability.Fixed in 140.14.0-1.el9_8.aa
Event History
Frequently Asked Questions
Which package variants are covered by this advisory?
The listed packages are redhat/firefox, redhat/firefox-debuginfo, redhat/firefox-debugsource, and redhat/firefox-x11. No Thunderbird package is listed in the affected software, despite several listed fixes also referencing Thunderbird.
Which Red Hat platform offerings are explicitly listed as affected?
The advisory lists Red Hat Enterprise Linux for IBM z Systems Extended Life Cycle, Red Hat Enterprise Linux Server for Power LE Update Services for SAP Solutions, Red Hat Enterprise Linux for ARM 64 Extended Update Support, and Red Hat Enterprise Linux for ARM 64.
What types of security impact are represented in the listed fixes?
The fixes include privilege escalation, information disclosure, mitigation bypass, site-isolation issues, use-after-free, race-condition, and integer-overflow weaknesses. Affected areas include Graphics, CanvasWebGL, ImageLib, Cookies, Shell Integration, DOM UI events and focus handling, and Data Loss Prevention.