A weakness has been reported in the Captcha module for Drupal, which can be exploited by malicious people to bypass certain security restrictions.

The weakness is caused due to an error within the validation of certain malformed responses. This can be exploited to bypass the captcha check by sending a specially crafted response.

The weakness is reported in Captcha 4.7.x versions prior to 4.7-1.2 and Captcha 5.x versions prior to 5.x-1.1.

Solution
Update to a fixed version.
Further details available to Secunia VIM customers

Provided and/or discovered by
Independently reported by the Drupal Security Team and William Smith.

Changelog
Further details available to Secunia VIM customers

Original Advisory
http://drupal.org/node/114364

Deep Links
Links available to Secunia VIM customers