In wolfSSL before 5.2.0, certificate validation may be bypassed during attempted authentication by a TLS 1.3 client to a TLS 1.3 server. This occurs when the sig_algo field differs between the certificate_verify message and the certificate message.

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 before 4.8.1 incorrectly skips OCSP verification in certain situations of irrelevant response data that contains the NoCheck extension.

wolfSSL 4.6.x through 4.7.x before 4.8.0 does not produce a failure outcome when the serial number in an OCSP request differs from the serial number in the OCSP response.

In wolfSSL through 4.6.0, a side-channel vulnerability in base64 PEM file decoding allows system-level (administrator) attackers to obtain information about secret RSA keys via a controlled-channel and side-channel attack on software running in isolated environments that can be single stepped, especially Intel SGX.

DoTls13CertificateVerify in tls13.c in wolfSSL before 4.7.0 does not cease processing for certain anomalous peer behavior (sending an ED22519, ED448, ECC, or RSA signature without the corresponding certificate). The client side is affected because man-in-the-middle attackers can impersonate TLS 1.3 servers.

RsaPad_PSS in wolfcrypt/src/rsa.c in wolfSSL before 4.6.0 has an out-of-bounds write for certain relationships between key size and digest size.

wolfSSL before 4.5.0 mishandles TLS 1.3 server data in the WAIT_CERT_CR state, within SanityCheckTls13MsgReceived() in tls13.c. This is an incorrect implementation of the TLS 1.3 client state machine. This allows attackers in a privileged network position to completely impersonate any TLS 1.3 servers, and read or modify potentially sensitive information between clients using the wolfSSL library and these TLS servers.

An issue was discovered in wolfSSL before 4.5.0. It mishandles the change_cipher_spec (CCS) message processing logic for TLS 1.3. If an attacker sends ChangeCipherSpec messages in a crafted way involving more than one in a row, the server becomes stuck in the ProcessReply() loop, i.e., a denial of service.

An issue was discovered in wolfSSL before 4.5.0, when single precision is not employed. Local attackers can conduct a cache-timing attack against public key operations. These attackers may already have obtained sensitive information if the affected system has been used for private key operations (e.g., signing with a private key).