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Vulnerability record · CVE-2021-28807 · published 3 June 2021

CVE-2021-28807: Qnap q\'center cross-site scripting vulnerability

Qnap · Q\'Center

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

5.4 CVSS 3.1 Medium EPSS 1.4% · top 29.0% CWE-79 · Cross-site scripting
5.4CVSS 3.1 base score, v2 3.5
1.4%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References, 4 tagged exploit
17 Jun 2026Last modified by NVD

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

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://www.qnap.com/zh-tw/security-advisory/qsa-21-20 Vendor Advisory
https://www.shielder.it/advisories/qnap-qcenter-post-auth-remote-code-execution-via-qpkg/ ExploitThird Party Advisory
https://www.shielder.it/advisories/qnap-qcenter-virtual-stored-xss/ ExploitThird Party Advisory
https://www.qnap.com/zh-tw/security-advisory/qsa-21-20 Vendor Advisory
https://www.shielder.it/advisories/qnap-qcenter-post-auth-remote-code-execution-via-qpkg/ ExploitThird Party Advisory
https://www.shielder.it/advisories/qnap-qcenter-virtual-stored-xss/ ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-28807), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.