CVE-2021-28800

Name: CVE-2021-28800
Creator: NVD / NIST
Published: 2021-06-24T07:15:07.58+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.43%

Last modified Jun 17, 2026

CVE-2021-28800 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 1.43% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

1.43%

69.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-78

Affected Software

Vendor	Product	Versions
Qnap	Qts	< 4.3.3.1624
Qnap	Qts	>= 4.3.4, < 4.3.6.1663

References

https://www.qnap.com/zh-tw/security-advisory/qsa-21-28Vendor Advisory
https://www.qnap.com/zh-tw/security-advisory/qsa-21-28Vendor Advisory

Timeline

Published: Jun 24, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-28800?

How severe is CVE-2021-28800?

CVE-2021-28800 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.43% probability of exploitation in the next 30 days.

How do I fix CVE-2021-28800?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-28800?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST