Question2Answer through 1.8.8 contains a session invalidation vulnerability that allows attackers with a previously obtained remember-me cookie to retain authenticated access by exploiting the forgot-password reset flow's failure to clear the sessioncode field in qa-include/app/users-edit.php. While the normal password-change flow in qa-include/pages/account.php explicitly clears the sessioncode to invalidate persistent qa_session cookies, the forgot-password handler qa_finish_reset_user() omits this step, allowing any valid persistent cookie issued before the reset to continue authenticating the account after the password reset completes.

qa-include/qa-install.php in Question2Answer before 1.7.5 allows remote attackers to create multiple user accounts.