Simple Machines Forum (SMF), probably 1.1.4, relies on "randomly generated static" to hinder brute-force attacks on the WAV file (aka audio) CAPTCHA, which allows remote attackers to pass the CAPTCHA test via an automated attack that considers Hamming distances. NOTE: this issue reportedly exists because of an insufficient fix for CVE-2007-3308.

Simple Machines Forum (SMF) 1.1.2 uses a concatenation method with insufficient randomization when creating a WAV file CAPTCHA, which allows remote attackers to pass the CAPTCHA test via an automated brute-force attack.