A vulnerability, which was classified as critical, has been found in xxyopen/201206030 novel-plus up to 5.1.3. Affected by this issue is the function ajaxLogin of the file novel-admin/src/main/java/com/java2nb/system/controller/LoginController.java of the component CATCHA Handler. The manipulation leads to authentication bypass by capture-replay. The attack may be launched remotely. The complexity of an attack is rather high. The exploitation is known to be difficult. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.