If an object prototype was corrupted by an attacker, they would have been able to set undesired attributes on a JavaScript object, leading to privileged code execution. This vulnerability affects Firefox < 102, Firefox ESR < 91.11, Thunderbird < 102, and Thunderbird < 91.11.
https://www.mozilla.org/security/advisories/mfsa2022-26/
https://www.mozilla.org/security/advisories/mfsa2022-25/