Red Hat Security Advisory: firefox security update
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.
AI Analysis
Technical Summary
The advisory details a comprehensive security update for Mozilla Firefox and Thunderbird distributed by Red Hat, fixing 31 CVEs related to multiple security weaknesses including mitigation bypasses, site isolation issues, privilege escalations, information disclosures, use-after-free vulnerabilities, race conditions, integer overflows, and same-origin policy bypasses. These vulnerabilities affect various components such as Graphics (CanvasWebGL, Canvas2D, ImageLib, Text), Networking (Cookies), DOM (UI Events, Navigation, Push Subscriptions, Core & HTML), JavaScript Engine (JIT, WebAssembly), Storage (Cache API), Safe Browsing, Audio/Video Playback, Shell Integration, and Remote Settings Client. The fixes are incorporated in Firefox ESR versions 115.39, 140.14, 153.1, and Firefox 154. The advisory is published by Red Hat Product Security as RHSA-2026:58899 for Red Hat Enterprise Linux 10 and related platforms.
Potential Impact
The vulnerabilities collectively could allow attackers to bypass security mitigations, escalate privileges, disclose sensitive information, bypass same-origin policies, and cause use-after-free conditions leading to potential arbitrary code execution or denial of service. The issues span critical browser components affecting rendering, networking, storage, and scripting, which could compromise browser security and user data confidentiality and integrity. The advisory rates the impact as Important (high severity). No known exploits in the wild are reported at this time.
Mitigation Recommendations
Red Hat has released an update for Firefox as part of Red Hat Enterprise Linux 10 and its variants that addresses all listed vulnerabilities. Users should apply the update as described in the Red Hat advisory RHSA-2026:58899 (https://access.redhat.com/errata/RHSA-2026:58899) to remediate these issues. No additional mitigation steps are indicated beyond applying the official update.
Red Hat Security Advisory: firefox security update
Description
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.
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The advisory details a comprehensive security update for Mozilla Firefox and Thunderbird distributed by Red Hat, fixing 31 CVEs related to multiple security weaknesses including mitigation bypasses, site isolation issues, privilege escalations, information disclosures, use-after-free vulnerabilities, race conditions, integer overflows, and same-origin policy bypasses. These vulnerabilities affect various components such as Graphics (CanvasWebGL, Canvas2D, ImageLib, Text), Networking (Cookies), DOM (UI Events, Navigation, Push Subscriptions, Core & HTML), JavaScript Engine (JIT, WebAssembly), Storage (Cache API), Safe Browsing, Audio/Video Playback, Shell Integration, and Remote Settings Client. The fixes are incorporated in Firefox ESR versions 115.39, 140.14, 153.1, and Firefox 154. The advisory is published by Red Hat Product Security as RHSA-2026:58899 for Red Hat Enterprise Linux 10 and related platforms.
Potential Impact
The vulnerabilities collectively could allow attackers to bypass security mitigations, escalate privileges, disclose sensitive information, bypass same-origin policies, and cause use-after-free conditions leading to potential arbitrary code execution or denial of service. The issues span critical browser components affecting rendering, networking, storage, and scripting, which could compromise browser security and user data confidentiality and integrity. The advisory rates the impact as Important (high severity). No known exploits in the wild are reported at this time.
Mitigation Recommendations
Red Hat has released an update for Firefox as part of Red Hat Enterprise Linux 10 and its variants that addresses all listed vulnerabilities. Users should apply the update as described in the Red Hat advisory RHSA-2026:58899 (https://access.redhat.com/errata/RHSA-2026:58899) to remediate these issues. No additional mitigation steps are indicated beyond applying the official update.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:58899
- Cve Count
- 31
- Additional Cves
- ["CVE-2026-74935","CVE-2026-74936","CVE-2026-74939","CVE-2026-74940","CVE-2026-74941","CVE-2026-74942","CVE-2026-74943","CVE-2026-74944","CVE-2026-74945","CVE-2026-74946","CVE-2026-74948","CVE-2026-74949","CVE-2026-74953","CVE-2026-74957","CVE-2026-74959","CVE-2026-74960","CVE-2026-74962","CVE-2026-74963","CVE-2026-74964","CVE-2026-74965","CVE-2026-74967","CVE-2026-74969","CVE-2026-74971","CVE-2026-74972","CVE-2026-74973","CVE-2026-74974","CVE-2026-74976","CVE-2026-74983","CVE-2026-74987","CVE-2026-74990"]
- Cvss Version
- null
Threat ID: 6a8c4c48acd9273b499be014
Added to database: 08/24/2026, 13:51:04 UTC
Last enriched: 08/24/2026, 13:58:03 UTC
Last updated: 08/24/2026, 22:52:13 UTC
Views: 4
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