CVE-2022-30525

CVE-2022-30525 is an OS command injection vulnerability (CWE-78) in the CGI program of certain Zyxel firewall firmware versions. By sending crafted requests to the vulnerable CGI program, an attacker can modify specific files on the appliance and inject and execute operating system commands. Successful exploitation yields command execution on the firewall itself, allowing an attacker to alter device files/configuration and potentially pivot into the protected network — the class of edge-device flaw commonly targeted by ransomware operators (ransomware use in this case is not yet confirmed). Organizations running affected Zyxel firewalls, particularly those with management interfaces reachable from the internet, are at risk. Exploitation is confirmed in the wild: the flaw was added to CISA's KEV on 2022-05-16, EPSS assigns a 99.9% 30-day exploitation probability (100th percentile), and no public PoC is catalogued yet.

What to do: Apply Zyxel's fixed firmware per the vendor's instructions immediately, as required by the CISA KEV listing. Until patched, restrict HTTP/HTTPS management access to the firewall to trusted source addresses only. Because exploitation is confirmed in the wild, prioritize internet-facing Zyxel firewalls and review devices for indicators of compromise such as modified configurations or unexpected administrative changes.