When clicking on a tel: link, USSD codes, specified after a \* character, would be included in the phone number. On certain phones, or on certain carriers, if the number was dialed this could perform actions on a user's account, similar to a cross-site request forgery attack.
*This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 97.
CWE-319, CWE-319