libraries/select_lang.lib.php in phpMyAdmin 4.0.x before 4.0.10.9, 4.2.x before 4.2.13.2, and 4.3.x before 4.3.11.1 includes invalid language values in unknown-language error responses that contain a CSRF token and may be sent with HTTP compression, which makes it easier for remote attackers to conduct a BREACH attack and determine this token via a series of crafted requests.