RHSA-2026:58898: 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.el8_10 - Upgrade
Upgrade
redhat/firefox-debuginfoto a version that resolves this vulnerability.Fixed in 140.14.0-1.el8_10 - Upgrade
Upgrade
redhat/firefox-debugsourceto a version that resolves this vulnerability.Fixed in 140.14.0-1.el8_10 - Upgrade
Upgrade
redhat/firefoxto a version that resolves this vulnerability.Fixed in 140.14.0-1.el8_10.aa - Upgrade
Upgrade
redhat/firefox-debuginfoto a version that resolves this vulnerability.Fixed in 140.14.0-1.el8_10.aa - Upgrade
Upgrade
redhat/firefox-debugsourceto a version that resolves this vulnerability.Fixed in 140.14.0-1.el8_10.aa - Upgrade
Upgrade
firefoxto a version that resolves this vulnerability.Fixed in 115.39 - Upgrade
Upgrade
firefoxto a version that resolves this vulnerability.Fixed in 140.14 - Upgrade
Upgrade
firefoxto a version that resolves this vulnerability.Fixed in 153.1 - Upgrade
Upgrade
firefoxto a version that resolves this vulnerability.Fixed in 154 - Upgrade
Upgrade
firefoxto a version that resolves this vulnerability.Patch CVE-2026-74983
Event History
Frequently Asked Questions
Which systems should be prioritized for review?
Prioritize systems running the redhat/firefox package, including deployments on Red Hat Enterprise Linux for IBM z Systems, x86_64 Extended Life Cycle, ARM 64 Extended Life Cycle, IBM z Systems Extended Life Cycle, and Power little endian Extended Life Cycle. The advisory also lists firefox-debuginfo and firefox-debugsource package artifacts.
Does this advisory confirm that Thunderbird packages are updated?
The security-fix list attributes multiple issues to both Firefox and Thunderbird, but the listed software contains only Firefox package artifacts. No Thunderbird package or version is identified in the provided advisory data.
Can patch status be determined from the provided information alone?
No. The provided data does not include affected versions, fixed versions, or package release numbers, so installed package versions must be checked against the full errata details.