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Known exploited · Zyxel

CVE-2022-30525: Zyxel Multiple Firewalls OS Command Injection Vulnerability

What it is

A command injection vulnerability in the CGI program of some Zyxel firewall versions could allow an attacker to modify specific files and then execute some OS commands on a vulnerable device.

Added May 16, 2022Due June 6, 2022CISA KEV catalog 2026.10.01

Vendor
Zyxel
Product
Multiple Firewalls
Added to KEV
May 16, 2022
CISA due date
June 6, 2022
Ransomware use
Unknown

What CISA requires

Apply updates per vendor instructions.

Forensic triage

No

What to do now

  1. Find every instance of Multiple Firewalls you run, including the forgotten ones, and check its version against the vendor advisory.
  2. Apply the vendor's fix or mitigation, before June 6, 2022 if you are bound by CISA's deadline, sooner if it faces the internet.
  3. Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
  4. Until every instance is patched, block the attack at the edge: a WAF in blocking mode stops OS command injection payloads, including Shellshock.

References

CVE-2022-30525 in the National Vulnerability Database

The Dome

Block it at the edge while you patch

The Dome's WAF runs the OWASP Core Rule Set in blocking mode and stops OS command injection payloads, including Shellshock before they reach your application.

See the Dome

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Source: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.