{"id":"CVE-2023-4473","published":"2023-11-30T01:40:09Z","modified":"2025-12-16T18:23:26Z","title":"A command injection vulnerability in the web server of the Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NAS542…","vendor":"Zyxel","product":"NAS326 firmware","tier":"core","eol":null,"affectedVersions":[{"vendor":"Zyxel","product":"NAS326 firmware","versions":["V5.21(AAZF.14)C0"]},{"vendor":"Zyxel","product":"NAS542 firmware","versions":["V5.21(ABAG.11)C0"]}],"description":{"text":"A command injection vulnerability in the web server of the Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NAS542 firmware version V5.21(ABAG.11)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands by sending a crafted URL to a vulnerable device.","provenance":"source","from":"CVE.org"},"summary":{"text":"The Zyxel NAS326 firmware (V5.21(AAZF.14)C0) and NAS542 firmware (V5.21(ABAG.11)C0) contain a command injection flaw in the web server, classed as improper neutralisation of special elements used in an OS command. An unauthenticated attacker with network access to the device can execute operating system commands by sending a crafted URL, with no user interaction or configuration required.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-11-01T01:04:28Z"},"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":"CVE.org CNA"},"epss":{"score":0.41348,"percentile":0.98671,"date":"2026-10-31","provenance":"source"},"kev":null,"vulncheckKev":{"dateAdded":"2024-04-28","exploitedFirstSeen":"2024-04-28","ransomware":false,"evidence":[{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2024-04-28&host_type=src&vulnerability=cve-2023-4473","date":"2024-04-28"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2024-04-29&host_type=src&vulnerability=cve-2023-4473","date":"2024-04-29"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2024-04-30&host_type=src&vulnerability=cve-2023-4473","date":"2024-04-30"},{"url":"https://isc.sans.edu/diary/Another+Day+Another+NAS+Attacks+against+Zyxel+NAS326+devices+CVE20234473+CVE20234474/30884","date":"2024-04-30"},{"url":"https://blog.xlab.qianxin.com/rapperbot/","date":"2025-06-17"}],"evidenceTotal":5,"provenance":"source"},"exploited":true,"otx":null,"cwes":[{"id":"CWE-78","name":"Improper Neutralization of Special Elements used in an OS Command"}],"references":[{"url":"https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-authentication-bypass-and-command-injection-vulnerabilities-in-nas-products","tags":["vendor-advisory"]},{"url":"https://bugprove.com/knowledge-hub/cve-2023-4473-and-cve-2023-4474-authentication-bypass-and-multiple-blind-os-command-injection-vulnerabilities-in-zyxel-s-nas-326-devices/","tags":[]}],"techniques":[],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2023-54328","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-54328","exploited":false,"exploitedSince":null,"provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[],"timeline":[{"date":"2023-11-30","kind":"published","label":"Published (CVE.org)","url":"https://www.cve.org/CVERecord?id=CVE-2023-4473","provenance":"source"},{"date":"2024-04-28","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2024-04-28&host_type=src&vulnerability=cve-2023-4473","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":null},"priority":{"score":61.6,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in VulnCheck KEV"},{"name":"Recent KEV listing","points":0.0,"detail":"added 917 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.73,"detail":"percentile 0.9867"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":0.0,"detail":"none found"},{"name":"Mentioned in OTX pulses","points":0.0,"detail":"0 pulses"},{"name":"CVSS severity","points":6.86,"detail":"base score 9.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}