NULL pointer dereference in coap_dtls_generate_cookie() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted DTLS handshake that triggers SSL_get_SSL_CTX() to return NULL.Referenceshttps://github.com/obgm/libcoap/issues/1746https://github.com/obgm/libcoap/pull/1750
