MantisBT before 1.2.18 uses the public_key parameter value as the key to the CAPTCHA answer, which allows remote attackers to bypass the CAPTCHA protection mechanism by leveraging knowledge of a CAPTCHA answer for a public_key parameter value, as demonstrated by E4652 for the public_key value 0.
Publication date: Fri, 08 Sep 2017 06:29:00 +0000