{"id":"CVE-2021-28800","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-28800","generatedAt":"2026-10-27T20:21:26.657Z","title":"A command injection vulnerability has been reported to affect QNAP NAS running legacy versions of QTS.","description":"A command injection vulnerability has been reported to affect QNAP NAS running legacy versions of QTS. If exploited, this vulnerability allows attackers to execute arbitrary commands in a compromised application. This issue affects: QNAP Systems Inc. QTS versions prior to 4.3.6.1663 Build 20210504; versions prior to 4.3.3.1624 Build 20210416. This issue does not affect: QNAP Systems Inc. QTS 4.5.3. QNAP Systems Inc. QuTS hero h4.5.3. QNAP Systems Inc. QuTScloud c4.5.5.","published":"2021-06-24T07:15:08.000Z","lastModified":"2026-06-17T03:46:53.000Z","status":"Modified","sourceIdentifier":"security@qnapsecurity.com.tw","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-78"],"affected":["qnap/qts"],"epss":{"score":0.01433,"percentile":0.72879,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (1.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://www.qnap.com/zh-tw/security-advisory/qsa-21-28","tags":["Vendor Advisory"],"source":"security@qnapsecurity.com.tw"},{"url":"https://www.qnap.com/zh-tw/security-advisory/qsa-21-28","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-28800","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}