{"schemaVersion":3,"id":"CVE-2021-28807","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"A post-authentication reflected XSS vulnerability has been reported to affect QNAP NAS running Q’center. If exploited, this vulnerability allows remote attackers to inject malicious code. QNAP have already fixed this vulnerability in the following versions of Q’center: QTS 4.5.3: Q’center v1.12.1012 and later QTS 4.3.6: Q’center v1.10.1004 and later QTS 4.3.3: Q’center v1.10.1004 and later QuTS hero h4.5.2: Q’center v1.12.1012 and later QuTScloud c4.5.4: Q’center v1.12.1012 and later","dates":{"published":"2021-06-03T02:45:14.015Z","modified":"2024-09-16T17:17:48.672Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":7.7,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":7.7,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":5.4,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","exploitability":null,"impact":null,"computed":false},{"version":"2.0","versionLabel":"v2.0","source":"NVD","score":3.5,"severity":"low","vector":"AV:N/AC:M/Au:S/C:N/I:P/A:N","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.0138,"percentile":0.71739,"severity":"low","asOf":"2026-10-20T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-20T00:00:00.000Z","baselineScore":0.0138},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.0138,"percentile":0.71739}],"last30":[{"date":"2026-09-20T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.0138,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.0138,"percentile":0.71739}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[{"id":"REF_7604A070C114CFD3","name":"Exploit Reference (shielder.it)","source":"reference","url":"https://www.shielder.it/advisories/qnap-qcenter-virtual-stored-xss/","maturity":"unknown","reliabilityScore":0.2,"verified":false,"type":null,"platforms":[],"requiresAuth":null,"exploitdb":null,"metasploit":null},{"id":"REF_BEC78A8FFA93DC5C","name":"Exploit Reference (shielder.it)","source":"reference","url":"https://www.shielder.it/advisories/qnap-qcenter-post-auth-remote-code-execution-via-qpkg/","maturity":"unknown","reliabilityScore":0.2,"verified":false,"type":null,"platforms":[],"requiresAuth":null,"exploitdb":null,"metasploit":null}],"exploitCount":2,"weaknesses":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","description":"The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.","type":"weakness","status":"Stable","abstraction":"Base","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/79.html"}],"affected":[{"vendor":"qnap systems inc.","product":"q’center","name":"Q’center","label":"q’center","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ unspecified, < v1.12.1012","noFixRecorded":false,"fixedIn":null},{"text":"≥ unspecified, < v1.10.1004","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ unspecified, < v1.12.1012 | ≥ unspecified, < v1.10.1004","eol":null,"hubHref":"/vendor/qnap_systems_inc/qcenter"},{"vendor":"qnap","product":"q\\'center","name":"q\\'center","label":"q\\'center","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 1.12.1012","noFixRecorded":false,"fixedIn":null},{"text":"< 1.10.1004","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.12.1012 | < 1.10.1004","eol":null,"hubHref":"/vendor/qnap/qcenter"}],"affectedCount":2,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://www.qnap.com/zh-tw/security-advisory/qsa-21-20","label":"www.qnap.com/zh-tw/security-advisory/qsa-21-20","hostname":"www.qnap.com","tags":["X Refsource MISC","Vendor Advisory"]},{"url":"https://www.shielder.it/advisories/qnap-qcenter-virtual-stored-xss/","label":"www.shielder.it/advisories/qnap-qcenter-virtual-stored-xss/","hostname":"www.shielder.it","tags":["X Refsource MISC","Exploit","Third Party Advisory"]},{"url":"https://www.shielder.it/advisories/qnap-qcenter-post-auth-remote-code-execution-via-qpkg/","label":"www.shielder.it/advisories/qnap-qcenter-post-auth-remote-code-execution-via-qpkg/","hostname":"www.shielder.it","tags":["X Refsource MISC","Exploit","Third Party Advisory"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2021-06-03T02:45:14.015Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2024-09-16T17:17:48.672Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":41,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-20T23:50:54.503Z","stale":false,"partial":false}}