When downloading files through the Save As dialog on Windows with suggested filenames containing environment variable names, Windows would have resolved those in the context of the current user. <br>*This bug only affects Firefox on Windows. Other versions of Firefox are unaffected.*. This vulnerability affects Firefox < 111, Firefox ESR < 102.9, and Thunderbird < 102.9.
https://www.mozilla.org/security/advisories/mfsa2023-11/
https://www.mozilla.org/security/advisories/mfsa2023-10/