{"id":"CVE-2023-28771","published":"2023-04-25T02:15:08Z","modified":"2026-06-17T05:48:44Z","title":"Zyxel Multiple Firewalls OS Command Injection Vulnerability","vendor":"Zyxel","product":"Multiple Firewalls","tier":"core","eol":null,"description":{"text":"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.","provenance":"source","from":"NVD"},"summary":{"text":"The vulnerability is an OS command injection flaw in the firmware of multiple Zyxel firewall families, specifically the ZyWALL/USG, VPN, USG FLEX, and ATP series, caused by improper handling of error messages. An unauthenticated remote attacker who can reach an affected device over the network can exploit it without user interaction by sending crafted packets to execute some operating system commands on the device.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T13:44:52Z"},"cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.99284,"percentile":0.99937,"date":"2026-10-29","provenance":"source"},"kev":{"dateAdded":"2023-05-31","dueDate":"2023-06-21","ransomware":false,"requiredAction":"Apply updates per vendor instructions.","notes":"https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls;   https://nvd.nist.gov/vuln/detail/CVE-2023-28771","provenance":"source"},"vulncheckKev":{"dateAdded":"2023-05-25","exploitedFirstSeen":"2023-05-25","ransomware":false,"evidence":[{"url":"https://cyberplace.social/@GossiTheDog/110428080243894672","date":"2023-05-25"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2023-05-31"},{"url":"https://www.fortinet.com/blog/threat-research/ddos-botnets-target-zyxel-vulnerability-cve-2023-28771","date":"2023-07-19"},{"url":"https://information.rapid7.com/rs/411-NAK-970/images/Rapid7-2023-Mid-Year-Threat-Review.pdf","date":"2023-08-17"},{"url":"https://sektorcert.dk/wp-content/uploads/2023/11/SektorCERT-The-attack-against-Danish-critical-infrastructure-TLP-CLEAR.pdf","date":"2023-11-10"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2023-11-18&host_type=src&vulnerability=cve-2023-28771","date":"2023-11-18"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2023-11-28&host_type=src&vulnerability=cve-2023-28771","date":"2023-11-28"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2023-11-29&host_type=src&vulnerability=cve-2023-28771","date":"2023-11-29"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2023-12-06&host_type=src&vulnerability=cve-2023-28771","date":"2023-12-06"},{"url":"https://blog.talosintelligence.com/content/files/2023/12/2023_Talos_Year_In_Review.pdf","date":"2023-12-07"}],"evidenceTotal":353,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"},{"name":"Actively_Exploited_Kev | Oct 18, 2026","url":"https://otx.alienvault.com/pulse/6ad38c22e1848f8189d1c121","created":"2026-10-17"}],"provenance":"machine"},"cwes":[{"id":"CWE-78","name":"Improper Neutralization of Special Elements used in an OS Command"}],"references":[{"url":"http://packetstormsecurity.com/files/172820/Zyxel-IKE-Packet-Decoder-Unauthenticated-Remote-Code-Execution.html","tags":["Exploit","Third Party Advisory"]},{"url":"https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls","tags":["Vendor Advisory"]},{"url":"http://packetstormsecurity.com/files/172820/Zyxel-IKE-Packet-Decoder-Unauthenticated-Remote-Code-Execution.html","tags":["Exploit","Third Party Advisory"]},{"url":"https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls","tags":["Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-28771","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: unauthenticated remote packets reach exposed firewall service","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"sending crafted packets to an affected device","start":335,"end":380}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1059","name":"Command and Scripting Interpreter","tactics":["execution"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: OS command execution on the firewall","mappingType":"primary_impact","evidence":[{"from":"description","quote":"could allow an unauthenticated attacker to execute some OS commands remotely","start":255,"end":331}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2023-32406","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-32406","exploited":true,"exploitedSince":"2023-05-31","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":1,"skipped":1,"earliest":"2023-05-23","earliestUrl":"https://github.com/benjaminhays/CVE-2023-28771-PoC","repos":[{"name":"benjaminhays/CVE-2023-28771-PoC","url":"https://github.com/benjaminhays/CVE-2023-28771-PoC","stars":30,"created":"2023-05-23"}]},"metasploit":[{"name":"Zyxel IKE Packet Decoder Unauthenticated Remote Code Execution","module":"exploit/linux/misc/zyxel_ike_decoder_rce_cve_2023_28771","type":"exploit","disclosureDate":"2023-03-31","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/misc/zyxel_ike_decoder_rce_cve_2023_28771.rb"}],"first":{"date":"2023-03-31","source":"Metasploit","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/misc/zyxel_ike_decoder_rce_cve_2023_28771.rb"},"provenance":"source"},"exploitRefs":["http://packetstormsecurity.com/files/172820/Zyxel-IKE-Packet-Decoder-Unauthenticated-Remote-Code-Execution.html"],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"primary","techniques":["T1059"],"provenance":"ai"}],"timeline":[{"date":"2023-03-31","kind":"exploit-public","label":"First public exploit: Metasploit; later: PoC-in-GitHub 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