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Mozilla Foundation Security Advisory 2020-37

Security Vulnerabilities fixed in Firefox ESR 68.12

Announced
August 25, 2020
Impact
high
Products
Firefox ESR
Fixed in
  • Firefox ESR 68.12

#CVE-2020-15663: Downgrade attack on the Mozilla Maintenance Service could have resulted in escalation of privilege

Reporter
Xiaoyin Liu
Impact
high
Description

If Firefox is installed to a user-writable directory, the Mozilla Maintenance Service would execute updater.exe from the install location with system privileges. Although the Mozilla Maintenance Service does ensure that updater.exe is signed by Mozilla, the version could have been rolled back to a previous version which would have allowed exploitation of an older bug and arbitrary code execution with System Privileges.
Note: This issue only affected Windows operating systems. Other operating systems are unaffected.

References

#CVE-2020-15664: Attacker-induced prompt for extension installation

Reporter
Kaizer Soze
Impact
high
Description

By holding a reference to the eval() function from an about:blank window, a malicious webpage could have gained access to the InstallTrigger object which would allow them to prompt the user to install an extension. Combined with user confusion, this could result in an unintended or malicious extension being installed.

References

#CVE-2020-15669: Use-After-Free when aborting an operation

Reporter
Jason Kratzer
Impact
high
Description

When aborting an operation, such as a fetch, an abort signal may be deleted while alerting the objects to be notified. This results in a use-after-free and we presume that with enough effort it could have been exploited to run arbitrary code.

References