Garbage Collection Vulnerability in JavaScript Variables: User-After-Poison and Potential Crash Exploit

CVE-2021-23960 · HIGH Severity

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Performing garbage collection on re-declared JavaScript variables resulted in a user-after-poison, and a potentially exploitable crash. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.

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