Oracle MySQL 5.5.38 and earlier, 5.6.19 and earlier, and MariaDB 5.5.28a, 5.3.11, 5.2.13, 5.1.66, and possibly other versions, generates different error messages with different time delays depending on whether a user name exists, which allows remote attackers to enumerate valid usernames.
| Software | From | Fixed in |
|---|---|---|
| mariadb / mariadb | 5.5.28a | 5.5.28a.x |
| oracle / mysql | 5.5.19 | 5.5.19.x |
| mariadb / mariadb | 5.2.13 | 5.2.13.x |
| mariadb / mariadb | 5.1.66 | 5.1.66.x |
| mariadb / mariadb | 5.3.11 | 5.3.11.x |