CVEs / CVE-2023-28771
CVE-2023-28771: Zyxel Multiple Firewalls OS Command Injection Vulnerability
- Known exploited in the CISA KEV catalog since 31 May 2023
- critical 9.8 CVSS 3.1 (from the CNA)
- EPSS 99.2% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
Zyxel ATP, USG FLEX, VPN, and ZyWALL/USG firewalls allow for improper error message handling which could allow an unauthenticated attacker to execute OS commands remotely by sending crafted packets to an affected device.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Zyxel ZyWALL/USG series firmware | 4.60 through 4.73 | — |
| Zyxel VPN series firmware | 4.60 through 5.35 | — |
| Zyxel USG FLEX series firmware | 4.60 through 5.35 | — |
| Zyxel ATP series firmware | 4.60 through 5.35 | — |
Exploitation
| In CISA KEV since | 31 May 2023 |
|---|---|
| Due date for US federal agencies | 21 Jun 2023 |
| Used in ransomware campaigns | Unknown |
| Required action | Apply updates per vendor instructions. |
Severity
| CVSS 3.1 | 9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-78 |
References
- CVE-2023-28771 on NVD
- CVE-2023-28771 in the CISA KEV catalog
- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls (cited by CISA)
- http://packetstormsecurity.com/files/172820/Zyxel-IKE-Packet-Decoder-Unauthenticated-Remote-Code-Execution.html Exploit, Third Party Advisory
- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-28771 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.