CVE-2026-45734

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=doresendactivatio...

EUVD-2026-61014

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=doresendactivatio...

CVE-2026-45734

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=doresendactivatio...

CVE-2026-45734 MyBB: Default CAPTCHA missing invalidation

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=doresendactivatio...

CVE-2026-45734

MyBB versions before 1.8.40 fail to call captcha::invalidate_captcha() in five endpoints (contact.php, member.php actions, sendthread.php), allowing a valid CAPTCHA response to be replayed for low-integrity abuse (spam, password reset floods). CVSS 5.3 MEDIUM. Fixed in 1.8.40; no in-the-wild expl...