CVE-2021-28806

DOM-Based XSS Vulnerability in QTS and QuTS hero

MEDIUM

5.4

CVSS Score

Published: June 3, 2021 at 02:45 AM UTC

Updated: June 17, 2026 at 03:46 AM UTC

3 products affected across 1 vendorQTSQuTS heroQuTScloud

Using QTS by QNAP Systems Inc.?

Get instant alerts when new vulnerabilities affect QTS - before attackers find them.

Real-time alertsTrack your software stackFree plan available

Start Free Sign In

Severity

MEDIUM5.4

Exploit prediction

EPSS 0.5%

Description

A DOM-based XSS vulnerability has been reported to affect QNAP NAS running QTS and QuTS hero. If exploited, this vulnerability allows attackers to inject malicious code. This issue affects: QNAP Systems Inc. QTS versions prior to 4.5.3.1652 Build 20210428. QNAP Systems Inc. QuTS hero versions prior to h4.5.2.1638 Build 20210414. QNAP Systems Inc. QuTScloud versions prior to c4.5.5.1656 Build 20210503. This issue does not affect: QNAP Systems Inc. QTS 4.3.6; 4.3.3.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

QTS · Qnap

95%

v < 4.5.3.1652v < 4.5.3.1652 Build 20210428

Vendor states this is fixed in 4.3.3 (unaffected)

Vendor states this is fixed in 4.3.6 (unaffected)

Affected range stops below 4.5.3.1652, so it looks safe — our inference, not a vendor statement

Affected range stops below 4.5.3.1652 Build 20210428, so it looks safe — our inference, not a vendor statement

QuTS hero · Qnap

95%

v < h4.5.2.1638v < h4.5.2.1638 Build 20210414

Affected range stops below h4.5.2.1638, so it looks safe — our inference, not a vendor statement

Affected range stops below h4.5.2.1638 Build 20210414, so it looks safe — our inference, not a vendor statement

QuTScloud · Qnap

95%

v < c4.5.5.1656v < c4.5.5.1656 Build 20210503

Affected range stops below c4.5.5.1656, so it looks safe — our inference, not a vendor statement

Affected range stops below c4.5.5.1656 Build 20210503, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://www.qnap.com/zh-tw/security-advisory/qsa-21-22

References (1)

x_refsource_MISCVendor Advisory

Source: [email protected]

https://www.qnap.com/zh-tw/security-advisory/qsa-21-22

CVSS

5.4MEDIUM[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: LOW
User Interaction: REQUIRED
Scope: CHANGED
Confidentiality: LOW
Integrity: LOW
Availability: NONE

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-79

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Create account Sign in

Free plan, no card