Download Firefox

Firefox is no longer supported on Windows 8.1 and below.

Please download Firefox ESR (Extended Support Release) to use Firefox.

Firefox is no longer supported on macOS 10.14 and below.

Please download Firefox ESR (Extended Support Release) to use Firefox.

Firefox Privacy Notice

Mozilla Foundation Security Advisory 2021-44

Security Vulnerabilities fixed in Firefox ESR 78.15

Announced
October 5, 2021
Impact
high
Products
Firefox ESR
Fixed in
  • Firefox ESR 78.15

#CVE-2021-38496: Use-after-free in MessageTask

Reporter
Yangkang of 360 ATA Team
Impact
high
Description

During operations on MessageTasks, a task may have been removed while it was still scheduled, resulting in memory corruption and a potentially exploitable crash.

References

#CVE-2021-38500: Memory safety bugs fixed in Firefox 93, Firefox ESR 78.15, and Firefox ESR 91.2

Reporter
Mozilla developers
Impact
high
Description

Mozilla developers and community members Andreas Pehrson and Christian Holler reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

References