CVE-2023-28771: Zyxel Multiple Firewalls OS Command Injection Vulnerability
CVE-2023-28771 · Severity: critical · CVSS 9.8 · Exploited in the wild · Published 2023-05-31
Improper error message handling in multiple Zyxel firewall series allows an unauthenticated remote attacker to execute OS commands by sending crafted packets to the device. The vulnerability stems from a flaw in the IKE packet decoder.
Yes. CVE-2023-28771 is known to be exploited in the wild, first recorded on 31 May 2023. Treat it as urgent.
How severe is CVE-2023-28771?
Critical severity, with a CVSS score of 9.8, published 31 May 2023.
Which products and versions are affected?
Zyxel ATP series firmware 4.60 through 5.35; Zyxel USG FLEX series firmware 4.60 through 5.35; Zyxel VPN series firmware 4.60 through 5.35; Zyxel ZyWALL/USG series firmware 4.60 through 4.73.
Is there a fix for CVE-2023-28771?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2023-28771 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2023-28771?
Check whether you run Zyxel Firewalls or Zyxel Multiple Firewalls. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Affected products
Zyxel ATP series firmware 4.60 through 5.35
Zyxel USG FLEX series firmware 4.60 through 5.35
Zyxel VPN series firmware 4.60 through 5.35
Zyxel ZyWALL/USG series firmware 4.60 through 4.73
Timeline
2023-05-31: disclosed: Vulnerability published and added to CISA KEV catalog
2023-05-31: kev added
2023-05-31: exploited: Reported as exploited in the wild at time of publication