static bool ikev2_get_dcookie(u_char *dcookie,  chunk_t st_ni,
			      ip_address *addr, u_int8_t *spiI)
{
	size_t addr_length;
	SHA1_CTX ctx_sha1;
	unsigned char addr_buff[
		sizeof(union { struct in_addr A;
			       struct in6_addr B;
		       })];

	addr_length = addrbytesof(addr, addr_buff, sizeof(addr_buff));
	SHA1Init(&ctx_sha1);
	SHA1Update(&ctx_sha1, st_ni.ptr, st_ni.len);
	SHA1Update(&ctx_sha1, addr_buff, addr_length);
	SHA1Update(&ctx_sha1, spiI, sizeof(*spiI));
	SHA1Update(&ctx_sha1, ikev2_secret_of_the_day,
		   SHA1_DIGEST_SIZE);
	SHA1Final(dcookie, &ctx_sha1);
	DBG(DBG_PRIVATE,
	    DBG_log("ikev2 secret_of_the_day used %s, length %d",
		    ikev2_secret_of_the_day,
		    SHA1_DIGEST_SIZE);
	    );

	DBG(DBG_CRYPT,
	    DBG_dump("computed dcookie: HASH(Ni | IPi | SPIi | <secret>)",
		     dcookie, SHA1_DIGEST_SIZE));
#if 0
	ikev2_secrets_recycle++;
	if (ikev2_secrets_recycle >= 32768) {
		/* handed out too many cookies, cycle secrets */
		ikev2_secrets_recycle = 0;
		/* can we call init_secrets() without adding an EVENT? */
		init_secrets();
	}
#endif
	return TRUE;
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.