Mozilla Firefox 154 Security Bulletin: Multiple High-Severity Vulnerabilities (Sandbox Escape/UAF)

Vulnerability Overview The Mozilla Foundation released security advisory 2026-74, which addresses multiple security vulnerabilities in Firefox 154. These vulnerabilities include sandbox escapes, site isolation issues, privilege escalation, use-after-free, mitigation bypasses, and information disclosure. Affected Versions Firefox 154: All users running this version of Firefox are potentially affected by these vulnerabilities. High-Risk Vulnerabilities: Several vulnerabilities are classified as “high” impact, leading to severe security issues such as sandbox escapes and privilege escalation. Moderate-Risk Vulnerabilities: Some vulnerabilities are classified as “moderate” impact, potentially resulting in information disclosure or clickjacking issues. Remediation Upgrade to Firefox 154: Users should immediately upgrade to Firefox 154 to patch these security vulnerabilities. Specific Fixes: Each vulnerability has specific remediation measures, such as fixes for the Remote Settings Client, CanvasWebGL, DOM: Networking, and other components. Vulnerability Details 1. CVE-2026-75874: Sandbox escape in the Remote Settings Client component - Reporter: crixer - Impact: high - Bug: 2039972 2. CVE-2026-74934: Site isolation issue in the Graphics: CanvasWebGL component - Reporter: satyamad - Impact: high - Bug: 2050594 3. CVE-2026-74935: Privilege escalation in the DOM: Networking component - Reporter: Yaqoub Aldurayhim - Impact: high - Bug: 2051013 4. CVE-2026-74936: Use-after-free in the JavaScript: WebAssembly component - Reporter: Amy Burnett of OpenAI - Impact: high - Bug: 2052688 5. CVE-2026-74937: Use-after-free in the JavaScript: GC component - Reporter: Amy Burnett of OpenAI - Impact: high - Bug: 2053337 6. CVE-2026-74938: Mitigation bypass in the JavaScript: GC component - Reporter: Amy Burnett of OpenAI - Impact: high - Bug: 2053688 7. CVE-2026-74939: Privilege escalation in the DOM: Navigation component - Reporter: chooseyeong - Impact: high - Bug: 2054416 8. CVE-2026-74940: Use-after-free in the Graphics: Text component - Reporter: kiyong - Impact: high - Bug: 2054842 9. CVE-2026-74941: Privilege escalation in the Graphics: CanvasWebGL component - Reporter: Jacolon Walker - Impact: high - Bug: 2055056 10. CVE-2026-74942: Privilege escalation in the Remote Settings Client component - Reporter: Gal Ankonina - Impact: high - Bug: 2056571 11. CVE-2026-74943: Use-after-free in the Graphics: ImageLib component - Reporter: Abdulaziz Alasaqah - Impact: high - Bug: 2057308 12. CVE-2026-74944: Use-after-free in the DOM: Core & HTML component - Reporter: Amy Burnett of OpenAI - Impact: high - Bug: 2057778 13. CVE-2026-74945: Information disclosure in the Graphics: Text component - Reporter: Abdulaziz Alasaqah - Impact: high - Bug: 2057808 14. CVE-2026-74946: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component - Reporter: locust1b - Impact: high - Bug: 2059997 15. CVE-2026-74947: Privilege escalation due to invalid pointers in the Graphics component - Reporter: navapon - Impact: high - Bug: 2060010 16. CVE-2026-74948: Information disclosure in the Graphics component - Reporter: Yaqoub Aldurayhim - Impact: high - Bug: 2060106 17. CVE-2026-74949: Privilege escalation due to use-after-free in the Graphics: Canvas2D component - Reporter: r00tdaddy - Impact: high - Bug: 2060245 18. CVE-2026-74950: Privilege escalation in the Downloads API component - Reporter: Frederik Braun - Impact: moderate - Bug: 1888253 19. CVE-2026-74951: Clickjacking issue in Firefox for Android - Reporter: Hafizh - Impact: moderate - Bug: 1978587 20. CVE-2026-74952: Privilege escalation in the Application Update component - Reporter: Tomoya Nakanishi - Impact: moderate - Bug: 2021757 21. CVE-2026-74953: Privilege escalation in the Networking: Cookies component - Reporter: Satoki Tsuji - Impact: moderate - Bug: 2022382 22. CVE-2026-74954: Information disclosure via side channel in the Storage: Cache API component - Reporter: Tomoya Nakanishi - Impact: moderate - Bug: 2023732 23. CVE-2026-74955: Privilege escalation in the Request Handling component - Reporter: jmwebdevelopement - Impact: moderate - Bug: 2029265 24. CVE-2026-74956: Same-origin policy bypass in the DOM: Service Workers component - Reporter: pakhunov.anton.n - Impact: moderate - Bug: 2032406 25. CVE-2026-74957: Mitigation bypass in the Safe Browsing component - Reporter: Tomoya Nakanishi - Impact: moderate - Bug: 2041906 26. CVE-2026-74958: Information disclosure in the WebRTC component - Reporter: Tomoya Nakanishi - Impact: moderate - Bug: 2045368 27. CVE-2026-74959: Mitigation bypass in the Storage: Cache API component - Reporter: David Bors at Snyk Security Labs - Impact: moderate - Bug: 2047853 28. CVE-2026-74960: Site isolation issue in the WebExtensions component - Reporter: Khanh Nguyen - Impact: moderate - Bug: 2049148 29. CVE-2026-74961: Side channel in the Web Audio component - Reporter: Rintaro Kawasugi - Impact: moderate - Bug: 2056

Goal Reached Thanks to every supporter — we hit 100%!

Mozilla Firefox 154 Security Bulletin: Multiple High-Severity Vulnerabilities (Sandbox Escape/UAF)