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Mozilla Foundation Security Advisory 2021-40

Security Vulnerabilities fixed in Firefox ESR 91.1

Announced
September 7, 2021
Impact
low
Products
Firefox ESR
Fixed in
  • Firefox ESR 91.1

#CVE-2021-38492: Navigating to "mk:" URL scheme could load Internet Explorer

Reporter
James Lee
Impact
moderate
Description

When delegating navigations to the operating system, Firefox would accept the mk scheme which might allow attackers to launch pages and execute scripts in Internet Explorer in unprivileged mode.
This bug only affects Firefox for Windows. Other operating systems are unaffected.

References

#CVE-2021-38495: Memory safety bugs fixed in Firefox 92 and Firefox ESR 91.1

Reporter
Mozilla developers and community
Impact
high
Description

Mozilla developers Tyson Smith, Christian Holler, and Gabriele Svelto reported memory safety bugs present in Firefox 91 and Firefox ESR 91.0. 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