An issue was discovered in Mbed TLS 3.x before 3.6.1. With TLS 1.3, when a server enables optional authentication of the client, if the client-provided certificate does not have appropriate values in if keyUsage or extKeyUsage extensions, then the return value of mbedtlssslgetverifyresult() would incorrectly have the MBEDTLSX509BADCERTKEYUSAGE and MBEDTLSX509BADCERTKEYUSAGE bits clear. As a result, an attacker that had a certificate valid for uses other than TLS client authentication would nonetheless be able to use it for TLS client authentication. Only TLS 1.3 servers were affected, and only with optional authentication (with required authentication, the handshake would be aborted with a fatal alert).

Mbed TLS 3.2.x through 3.4.x before 3.5 has a Buffer Overflow that can lead to remote Code execution.

An issue was discovered in Mbed TLS before 2.28.9 and 3.x before 3.6.1, in which the user-selected algorithm is not used. Unlike previously documented, enabling MBEDTLSPSAHMACDRBGMDTYPE does not cause the PSA subsystem to use HMACDRBG: it uses HMACDRBG only when MBEDTLSPSACRYPTOEXTERNALRNG and MBEDTLSCTRDRBGC are disabled.