wolfSSL 5.x before 5.1.1 uses non-random IV values in certain situations. This affects connections (without AEAD) using AES-CBC or DES3 with TLS 1.1 or 1.2 or DTLS 1.1 or 1.2. This occurs because of misplaced memory initialization in BuildMessage in internal.c.

wolfSSL through 5.0.0 allows an attacker to cause a denial of service and infinite loop in the client component by sending crafted traffic from a Machine-in-the-Middle (MITM) position. The root cause is that the client module accepts TLS messages that normally are only sent to TLS servers.