Quoting upstream PostgreSQL security page: http://www.postgresql.org/support/security.html

If PostgreSQL is configured with LDAP authentication, and your LDAP configuration allows anonymous binds, it is possible for a user to authenticate themselves with an empty password.

Affected versions: 8.3, 8.2

Fixed in versions: 8.3.8, 8.2.14

Severity: A - A vulnerability that is exploitable for privilege escalation without requiring a prior login.

A security flaw was found in the way DES and extended DES based crypt() password encryption function performed encryption of certain keys, when the key to be encrypted was provided in the Unicode encoding (certain keys were truncated before being DES digested). When the resulting ciphertext for such a previously shortened key was used as a pattern in a password protected resource, intended to be matched against subsequently encrypted value of the password field, retrieved from the user authentication dialog, it could lead to authentication bypass.

End of life: 2/7/2013, Latest version: 8.3.23

End of life: 2/7/2013, Latest version: 8.3.23