Mozilla Foundation Security Advisory 2026-98

Security Vulnerabilities fixed in Firefox ESR 115.42

Announced

September 29, 2026

Impact

high

Products

Firefox ESR

Fixed in

Firefox ESR 115.42

Note: We have changed how we publish advisories. We no longer roll all internally identified memory safety vulnerabilities into a single CVE and are now issuing an advisory for every individual bug.

#CVE-2026-100756: Incorrect boundary conditions in the Audio/Video: Playback component

Reporter: Mozilla
Impact: high

References

Bug 2047721

#CVE-2026-100757: Use-after-free in the Widget component

Reporter: Mohamed Mbarek
Impact: high

References

Bug 2049352

#CVE-2026-100758: Sandbox escape in the DOM: Navigation component

Reporter: Mozilla
Impact: high

References

Bug 2049792

#CVE-2026-100759: Uninitialized memory in the Storage: Quota Manager component

Reporter: Mozilla
Impact: high

References

Bug 2054736

#CVE-2026-100762: Sandbox escape due to use-after-free in the DOM: Content Processes component

Reporter: Yaqoub Aldurayhim
Impact: high

References

Bug 2059404

#CVE-2026-92035: Sandbox escape due to incorrect boundary conditions in the Graphics component

Reporter: Mozilla
Impact: high

References

Bug 2061245

#CVE-2026-100766: Information disclosure in the Networking: JAR component

Reporter: Mozilla
Impact: high

References

Bug 2061526

#CVE-2026-100767: Use-after-free in the Networking: Cache component

Reporter: Mozilla
Impact: high

References

Bug 2063680

#CVE-2026-100770: Sandbox escape due to use-after-free in the DOM: Content Processes component

Reporter: Mozilla
Impact: high

References

Bug 2068322

#CVE-2026-100771: Undefined behavior in the DOM: Streams component

Reporter: Mozilla
Impact: high

References

Bug 2068336

#CVE-2026-100773: Use-after-free in the Storage: IndexedDB component

Reporter: Mozilla
Impact: high

References

Bug 2068346

#CVE-2026-100774: Use-after-free in the DOM: Core & HTML component

Reporter: Mozilla
Impact: high

References

Bug 2068351

#CVE-2026-100775: Sandbox escape in the Graphics component

Reporter: Mozilla
Impact: high

References

Bug 2068367

#CVE-2026-100777: Use-after-free in the Graphics: Canvas2D component

Reporter: Mozilla
Impact: high

References

Bug 2068375

#CVE-2026-100778: Sandbox escape due to use-after-free in the DOM: Core & HTML component

Reporter: Mozilla
Impact: high

References

Bug 2068406

#CVE-2026-100779: Use-after-free in the XSLT component

Reporter: Mozilla
Impact: high

References

Bug 2068417

#CVE-2026-100780: Use-after-free in the DOM: Core & HTML component

Reporter: Mozilla
Impact: high

References

Bug 2068422

#CVE-2026-100781: Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component

Reporter: Mozilla
Impact: high

References

Bug 2068434

#CVE-2026-100782: Privilege escalation due to incorrect boundary conditions in the Graphics component

Reporter: Mozilla
Impact: high

References

Bug 2068456

#CVE-2026-100783: Uninitialized memory in the Audio/Video component

Reporter: 5up3rh3i
Impact: high

References

Bug 2069804

#CVE-2026-100784: Use-after-free in the Layout: Text and Fonts component

Reporter: 5up3rh3i
Impact: high

References

Bug 2070264

#CVE-2026-100785: Use-after-free in the DOM: Core & HTML component

Reporter: Mozilla
Impact: high

References

Bug 2071064

#CVE-2026-100786: Sandbox escape due to use-after-free in the Graphics component

Reporter: Mozilla
Impact: high

References

Bug 2071067

#CVE-2026-100789: Use-after-free in the Graphics: Canvas2D component

Reporter: Mozilla
Impact: high

References

Bug 2072429

#CVE-2026-100790: Use-after-free in the XSLT component

Reporter: Mozilla
Impact: high

References

Bug 2072432

#CVE-2026-100791: Use-after-free in the DOM: Core & HTML component

Reporter: Mozilla
Impact: high

References

Bug 2072433

#CVE-2026-100832: Use-after-free in the Graphics: Canvas2D component

Reporter: Mozilla
Impact: high

References

Bug 2072467

#CVE-2026-100797: Privilege escalation due to use-after-free in the Graphics: WebRender component

Reporter: Mozilla
Impact: moderate

References

Bug 2050542

#CVE-2026-100803: Same-origin policy bypass in the WebExtensions component

Reporter: Yaqoub Aldurayhim
Impact: moderate

References

Bug 2057988

#CVE-2026-100819: Sandbox escape due to incorrect boundary conditions in the XPCOM component

Reporter: Mozilla
Impact: moderate

References

Bug 2071069

#CVE-2026-100821: Site isolation issue in the Panning and Zooming component

Reporter: Nguyen Thanh Nguyen
Impact: moderate

References

Bug 2071784