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CVE-2023-28771

98
FAUCET Score

CVE-2023-28771 is a critical vulnerability affecting Zyxel ZyWALL/USG, VPN, USG FLEX, and ATP series devices, stemming from improper error message handling that allows unauthenticated remote OS command execution. With a CVSS score of 9.8 (CRITICAL), this flaw is easily exploitable over the network without user interaction and can lead to complete compromise of confidentiality, integrity, and availability. This vulnerability is actively exploited in the wild, with public exploit code available (e.g., Metasploit), and has garnered significant community discussion and media attention.

Impacted Technologies

VendorProductVersion(s)CPE
>= 4.60, < 5.36CPE matchmatch criteria
cpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
>= 4.60, < 5.35CPE matchmatch criteria
cpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
>= 4.60, < 5.36CPE matchmatch criteria
cpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
>= 4.60, < 5.36CPE matchmatch criteria
cpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*
>= 4.60, < 5.36CPE matchmatch criteria
cpe:2.3:o:zyxel:atp700_firmware:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
99.28%
Probability of exploitation in next 30 days
EPSS Percentile
99.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
Added to KEV · May 31, 2023
Metasploit: Zyxel IKE Packet Decoder Unauthenticated Remote Code Execution · Mar 31, 2023
This CVE's current EPSS score of 0.9928 is in the 100th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

cisa.gov / known-exploited-vulnerabilities-catalog
US Government Resource
packetstormsecurity.com / files/172820/Zyxel-IKE-Packet-Decoder-Unauthenticated-Remote-Code-Execution.html
ExploitThird Party Advisory
zyxel.com / global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls
Vendor Advisory