Is CVE-2026-41539 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-41539 being exploited in the wild.

How severe is CVE-2026-41539?

Informational severity, with a CVSS score of 8.7, published 9 June 2026.

Which products and versions are affected?

QNAP Systems, Inc. QuTS hero h5.2.9.3499 build 20260514 and earlier; h5.3.4.3500 build 20260520 and earlier; h6.0.0.3500 build 20260520 and earlier.

Is there a fix for CVE-2026-41539?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-41539 attacked?

It is attacked over the network, in an operating system.

Am I affected by CVE-2026-41539?

Check whether you run QNAP Systems or Inc. QuTS hero at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-41539: QNAP QTS and QuTS hero cross-site scripting

CVE-2026-41539 · Severity: info · CVSS 8.7 · Published 2026-06-09

A security vulnerability has been identified in QNAP storage device operating systems, including QTS and QuTS hero. This flaw allows remote attackers to execute malicious scripts in a user's browser if they are tricked into visiting a specific link. Successful exploitation could allow an attacker to bypass security controls, steal sensitive session information, or access application data stored on the device.

Technologies: QNAP Systems, Inc. QuTS hero. Vendors: QNAP Systems, Inc..

Quick answers

Is CVE-2026-41539 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-41539 being exploited in the wild.
How severe is CVE-2026-41539?: Informational severity, with a CVSS score of 8.7, published 9 June 2026.
Which products and versions are affected?: QNAP Systems, Inc. QuTS hero h5.2.9.3499 build 20260514 and earlier; h5.3.4.3500 build 20260520 and earlier; h6.0.0.3500 build 20260520 and earlier.
Is there a fix for CVE-2026-41539?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-41539 attacked?: It is attacked over the network, in an operating system.
Am I affected by CVE-2026-41539?: Check whether you run QNAP Systems or Inc. QuTS hero at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A cross-site scripting (XSS) vulnerability (CWE-79) exists in several QNAP operating system versions, including QTS and QuTS hero. The vulnerability stems from improper neutralization of input during web page generation. A remote attacker can exploit this by enticing a user to interact with a malicious link or page, leading to the execution of arbitrary script code in the context of the victim's browser session. This can be used to bypass security mechanisms or access sensitive application data. QNAP has released patches for QTS 5.2.x and QuTS hero h5.2.x, h5.3.x, and h6.0.x.

Affected products

QNAP Systems, Inc. QTS 5.2.9.3492 build 20260507 and earlier
QNAP Systems, Inc. QuTS hero h5.2.9.3499 build 20260514 and earlier; h5.3.4.3500 build 20260520 and earlier; h6.0.0.3500 build 20260520 and earlier

Timeline

2026-06-09: disclosed
2026-06-09: advisory

References

https://www.qnap.com/en/security-advisory/qsa-26-31

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.