CVE-2021-23975

high

Published — · Modified —

CVSS v3

—

CVSS v2

—

VIR risk

8.0

Description

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 we incorrectly called the sizeof function, instead of using the API method that checks for invalid pointers. This vulnerability affects Firefox < 86.

Predictions

Exploit likelihood

20%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-23975

vendor Authored 2026-05-27

Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2021-23975.html

OS impact

OS	Version	Status	Fixed in
arch		fixed	`86.0-1`
sles		affected
debian	sid	fixed	`86.0-1`

References

https://www.suse.com/security/cve/CVE-2021-23975.html
https://security-tracker.debian.org/tracker/CVE-2021-23975

Verify integrity in audit chain (admin only). AS-IS.