static void free_sessions(void)
{
    simple_ssl_session *sess, *tsess;
    for (sess = first; sess;) {
        OPENSSL_free(sess->id);
        OPENSSL_free(sess->der);
        tsess = sess;
        sess = sess->next;
        OPENSSL_free(tsess);
    }
    first = NULL;
}

This vulnerability category highlights issues in resource management where failures to properly release memory, file handles, or other resources can degrade system performance or enable denial-of-service conditions.