Improper Input Validation
WordPress before 2.6.2 does not properly handle MySQL warnings about insertion of username strings that exceed the maximum column width of the user_login column, and does not properly handle space characters when comparing usernames, which allows remote attackers to change an arbitrary user's password to a random value by registering a similar username and then requesting a password reset, related to a "SQL column truncation vulnerability." NOTE: the attacker can discover the random password by also exploiting CVE-2008-4107.
CWE-20 - Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.