CVE-2025-4921 Information

Description

An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes. This vulnerability affects Firefox < 138.0.4 and Firefox ESR < 128.10.1.

Reference

https://bugzilla.mozilla.org/show_bug.cgi?id=1966614 https://www.mozilla.org/security/advisories/mfsa2025-36/ https://www.mozilla.org/security/advisories/mfsa2025-37/