What is CVE-2026-41539?

CVE-2026-41539 is a medium-severity vulnerability in QNAP Qts, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-06-09.

How severe is CVE-2026-41539?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in QNAP Qts

CVE-2026-41539

A cross-site scripting (XSS) vulnerability has been reported to affect several QNAP operating system versions. The remote attackers can then exploit the vulnerability to bypass security mechanisms or read application data. We have already fixed the vulnerability in the following versions: QTS 5.2.9.3492 build 20260507 and later QuTS hero h5.2.9.3499 build 20260514 and later QuTS hero h5.3.4.3500 build 20260520 and later QuTS hero h6.0.0.3500 build 20260520 and later

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-06-09 · last modified 2026-07-23.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (23.3th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

QNAP Qts — versions 5.2.0.2737, 5.2.0.2744, 5.2.0.2782
QNAP Quts Hero — versions h5.2.0.2737, h5.2.0.2782, h5.2.0.2789
QNAP Systems Inc. Qts — versions 5.2.0
QNAP Systems Inc. Quts Hero — versions h5.2.0, h5.3.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

Frequently asked questions

What is CVE-2026-41539?: CVE-2026-41539 is a medium-severity vulnerability in QNAP Qts, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-06-09.
How severe is CVE-2026-41539?: Medium severity. CVSS v3 base score is 6.1 out of 10.