Vulnerability Advisory : Heap Use-After-Free in PQC Hybrid KeyShare Error Cleanup in wolfSSL TLS 1.3 with LOW Attack Complexity

A heap use-after-free exists in wolfSSL's TLS 1.3 post-quantum cryptography (PQC) hybrid KeyShare processing. In the error handling path of TLSX_KeyShare_ProcessPqcHybridClient() in src/tls.c, the inner function TLSX_KeyShare_ProcessPqcClient_ex() frees a KyberKey object upon encountering an error. The caller then invokes TLSX_KeyShare_FreeAll(), which attempts to call ForceZero() on the already-freed KyberKey, resulting in writes of zero bytes over freed heap memory.