In PHP versions:8.1.* before 8.1.33, 8.2.* before 8.2.29, 8.3.* before 8.3.23, 8.4.* before 8.4.10 some functions like fsockopen() lack validation that the hostname supplied does not contain null characters. This may lead to other functions like parse_url() treat the hostname in different way, thus opening way to security problems if the user code implements access checks before access using such functions.
CWE-918