On BIG-IP 11.5.1-11.5.4, 11.6.1, and 12.1.0, a virtual server configured with a Client SSL profile may be vulnerable to a chosen ciphertext attack against CBC ciphers. When exploited, this may result in plaintext recovery of encrypted messages through a man-in-the-middle (MITM) attack, despite the attacker not having gained access to the server's private key itself. (CVE-2019-6593 also known as Zombie POODLE and GOLDENDOODLE.)

DBS3900 TDD LTE V100R003C00, V100R004C10 have a weak encryption algorithm security vulnerability. DBS3900 TDD LTE supports SSL/TLS protocol negotiation using insecure encryption algorithms. If an insecure encryption algorithm is negotiated in the communication, an unauthenticated remote attacker can exploit this vulnerability to crack the encrypted data and cause information leakage.