CyberRota Analysis
AI-GeneratedMyBB forum software versions prior to 1.8.40 are vulnerable due to a flaw in the CAPTCHA implementation, which fails to enforce single-use semantics, allowing attackers to bypass CAPTCHA protections through challenge replay. This could lead to unauthorized actions such as account activation or password resets, potentially compromising user accounts. Administrators of MyBB installations should prioritize upgrading to version 1.8.40 to mitigate this security risk.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
Note: these links are listed for security research and verification purposes only.
Original NVD Description
MyBB is free and open source forum software. Prior to 1.8.40, the built-in CAPTCHA does not consistently enforce single-use semantics, allowing remote attackers to bypass CAPTCHA controls through challenge replay. The successful validation paths in contact.php, member.php?action=do_resendactivation, member.php?action=do_lostpw, member.php?action=do_emailuser, and sendthread.php?action=do_sendtofriend do not call captcha::invalidate_captcha() for the MyBB Default CAPTCHA selected by the captchaimage setting. A valid response can therefore be reused until a non-vulnerable endpoint invalidates it, an incorrect response is submitted, or the challenge expires. This issue is fixed in version 1.8.40.