ARM mbed TLS before 1.3.21 and 2.x before 2.1.9, if optional authentication is configured, allows remote attackers to bypass peer authentication via an X.509 certificate chain with many intermediates. NOTE: although mbed TLS was formerly known as PolarSSL, the releases shipped with the PolarSSL name are not affected.

An exploitable free of a stack pointer vulnerability exists in the x509 certificate parsing code of ARM mbed TLS before 1.3.19, 2.x before 2.1.7, and 2.4.x before 2.4.2. A specially crafted x509 certificate, when parsed by mbed TLS library, can cause an invalid free of a stack pointer leading to a potential remote code execution. In order to exploit this vulnerability, an attacker can act as either a client or a server on a network to deliver malicious x509 certificates to vulnerable applications.

Arm Mbed TLS before 2.14.1, before 2.7.8, and before 2.1.17 allows a local unprivileged attacker to recover the plaintext of RSA decryption, which is used in RSA-without-(EC)DH(E) cipher suites.

ARM mbed TLS before 2.1.11, before 2.7.2, and before 2.8.0 has a buffer over-read in ssl_parse_server_key_exchange() that could cause a crash on invalid input.