CVE-2017-12871 (simplesamlphp)

The aesEncrypt method in lib/SimpleSAML/Utils/Crypto.php in SimpleSAMLphp 1.14.x through 1.14.11 makes it easier for context-dependent attackers to bypass the encryption protection mechanism by leveraging use of the first 16 bytes of the secret key as the initialization vector (IV).

Source: CVE-2017-12871 (simplesamlphp)