CVE-2021-23975

CVE-2021-23975 is a medium-severity vulnerability affecting Mozilla Firefox versions prior to 86. It stems from an incorrect function call within the about:memory developer page's Measure function, where sizeof was used instead of an API method for checking invalid pointers. This flaw has a CVSS score of 6.5, indicating a network-based attack requiring user interaction, with a potential impact of high integrity loss but no confidentiality or availability impact. While there is no known active exploitation, public exploit code, or KEV listing, the vulnerability has garnered some community discussion and media coverage.