Heap-based Buffer Over-read in Mbed TLS Affects Multiple Versions

CVE-2022-35409

Summary

An issue exists in Mbed TLS versions prior to 2.28.1 and 3.x before 3.2.0, where certain configurations leave DTLS servers vulnerable to an unauthenticated attack. An attacker can send an invalid ClientHello message that may cause a heap-based buffer over-read of up to 255 bytes. This vulnerability potentially leads to server crashes or information leaks based on the nature of the error responses. The specific configurations that are at risk include those with MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE enabled and MBEDTLS_SSL_IN_CONTENT_LEN set below a threshold, which may vary from 258 bytes (with mbedtls_ssl_cookie_check) to as high as 571 bytes (with custom cookie check functions).

References