Related Vulnerabilities: CVE-2021-23975  

A security issue was found in Firefox before version 86.0. The developer page about:memory has a Measure function for exploring what object types the browser has allocated and their sizes. When this function was invoked Firefox incorrectly called the sizeof function, instead of using the API method that checks for invalid pointers.

Severity Low

Remote No

Type Incorrect calculation

Description

A security issue was found in Firefox before version 86.0. The developer page about:memory has a Measure function for exploring what object types the browser has allocated and their sizes. When this function was invoked Firefox incorrectly called the sizeof function, instead of using the API method that checks for invalid pointers.

AVG-1599 firefox 85.0.2-1 86.0-1 High Fixed

https://www.mozilla.org/en-US/security/advisories/mfsa2021-07/#CVE-2021-23975
https://bugzilla.mozilla.org/show_bug.cgi?id=1685145