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CVE-2023-28771

Published: Apr 25, 2023Updated: Oct 27, 2025 Sources: CVE List NVD BDUCWE-78
NVD MITRE
9.8CVSSCRITICAL
EPSS Score
99.3%
Top 0.1%
CISA KEV
Active Exploitation
Since May 31, 2023
Exploits
1 Known
Remediation
Patch Available

Description

Improper error message handling in Zyxel ZyWALL/USG series firmware versions 4.60 through 4.73, VPN series firmware versions 4.60 through 5.35, USG FLEX series firmware versions 4.60 through 5.35, and ATP series firmware versions 4.60 through 5.35, which could allow an unauthenticated attacker to execute some OS commands remotely by sending crafted packets to an affected device.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-78

Affected Products

ZyWALL/USG series firmwareZyxelNetworking Infrastructure
VPN series firmwareZyxelNetworking Infrastructure
USG FLEX series firmwareZyxelNetworking Infrastructure
ATP series firmwareZyxelNetworking Infrastructure
ATP100Zyxel Communications Corp.Networking Infrastructure
zyxelcommercialTWNetworking Infrastructureaka zyxel communications corp.
zyxel communications corp.commercialTWNetworking Infrastructure
and 37 more affected products View all →

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

CISA Known Exploited Vulnerability
Added to KEV:May 31, 2023
Remediation due:Jun 21, 2023

Required action: Apply updates per vendor instructions.

1 exploit source identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
Official Patch Available

MITRE ATT&CK

1 technique
Execution
View detailed technique mapping

References

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls
zyxel.com
http://packetstormsecurity.com/files/172820/Zyxel-IKE-Packet-Decoder-Unauthenticated-Remote-Code-Execution.html
packetstormsecurity.com
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-28771
cisa.gov

Timeline

Published
Apr 25, 2023
Added to CISA KEV
May 31, 2023
Last Updated
Oct 27, 2025
News mentions
2

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