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QNAP Security Advisory
QSA-21-28 – Command Injection Vulnerability in QTS

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QSA-21-28 QNAP had published security enhancement against security vulnerabilities that could affect specific versions of QNAP products. Please use the following information and solutions to correct the security issues and vulnerabilities.

Command Injection Vulnerability in QTS

Release date: June 24, 2021
Security ID: QSA-21-28
Severity rating: High
CVE identifier: CVE-2021-28800
Affected products: Certain QNAP NAS


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.

We have already fixed this vulnerability in the following versions:

  • QTS Build 20210504 and later
  • QTS Build 20210416 and later

The latest versions of QTS, QuTS hero, and QuTScloud are not affected.


To secure your device, we strongly recommend updating your system to the latest version to benefit from vulnerability fixes. You can check the product support status to see the latest updates available to your NAS model.

Updating QTS or QuTS hero

  1. Log on to QTS or QuTS hero as administrator.
  2. Go to Control Panel> System> Firmware Update.
  3. Under Live Update, click Check for Update.
    QTS or QuTS hero downloads and installs the latest available update.

Tip: You can also download the update from the QNAP website. Go to Support> Download Center and then perform a manual update for your specific device.

Acknowledgements: CFF of Topsec Alpha Team
Revision History: V1.0 (June 24, 2021) – Published If you have any questions regarding this issue, please contact us at