Mozilla Foundation Security Advisory 2021-38

Security Vulnerabilities fixed in Firefox 92

Announced
September 7, 2021
Impact
high
Products
Firefox
Fixed in
  • Firefox 92

#CVE-2021-29993: Handling custom intents could lead to crashes and UI spoofs

Reporter
Amy Burnett working with Include Security
Impact
high
Description

Firefox for Android allowed navigations through the intent:// protocol, which could be used to cause crashes and UI spoofs.
This bug only affects Firefox for Android. Other operating systems are unaffected.

References

#CVE-2021-38491: Mixed-Content-Blocking was unable to check opaque origins

Reporter
Jonathan Kingston
Impact
moderate
Description

Mixed-content checks were unable to analyze opaque origins which led to some mixed content being loaded.

References

#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-2021-38493: Memory safety bugs fixed in Firefox 92, Firefox ESR 78.14 and Firefox ESR 91.1

Reporter
Mozilla developers and community
Impact
high
Description

Mozilla developers Gabriele Svelto and Tyson Smith reported memory safety bugs present in Firefox 91 and Firefox ESR 78.13. 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

#CVE-2021-38494: Memory safety bugs fixed in Firefox 92

Reporter
Mozilla developers and community
Impact
high
Description

Mozilla developers Christian Holler and Lars T Hansen reported memory safety bugs present in Firefox 91. 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