CVE-2024-28755: 
Mbed TLS vulnerability analysis and mitigation

An issue was discovered in Mbed TLS 3.5.x before 3.6.0. When an SSL context was reset with the mbedtls_ssl_session_reset() API, the maximum TLS version to be negotiated was not restored to the configured one. This vulnerability was discovered and reported by hey3e (GitHub Profile, Security Blog).

The vulnerability occurs in the mbedtls_ssl_session_reset() API functionality. When this API is called to reset an SSL context, it fails to properly restore the maximum TLS version that should be negotiated to the originally configured value. This implementation flaw affects the TLS version negotiation process (NVD, Mbed TLS Release).

The vulnerability allows an attacker to prevent an Mbed TLS server from establishing any TLS 1.3 connection. This can result in either a Denial of Service (DoS) or force a version downgrade from TLS 1.3 to TLS 1.2, potentially exposing the connection to lesser security protections (Mbed TLS Release).

The vulnerability can be exploited by an attacker who can interact with the TLS server. The attack requires network access but does not require authentication. The issue has been assigned a CVSS v3.1 Base Score of 6.5 MEDIUM (Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L) (NVD).

The vulnerability has been fixed in Mbed TLS version 3.6.0. Users should upgrade to this version or later to address the issue. The fix restores the maximum TLS version to be negotiated to the configured one when an SSL context is reset (Mbed TLS Release).