# CVE-2026-41539: QTS, QuTS hero

> Remote attackers can exploit an XSS vulnerability in QNAP operating systems to bypass security mechanisms or read application data.

- **Severity:** Medium 6.3 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 9 Jun 2026
- **Updated:** 19 Oct 2026
- **Also known as:** GHSA-hc5c-8r54-29r3

## What is CVE-2026-41539?

CVE-2026-41539 is a medium-severity cross-site scripting vulnerability in Qnap Qts, published on 9 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-41539?

It affects 2 products.


Products: Qnap Qts, Qnap Quts Hero.

## How do I fix CVE-2026-41539?

No fix has been published for CVE-2026-41539 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-41539 being exploited?

There is no known exploitation of CVE-2026-41539 in the wild and no public exploit code.

## Other vulnerabilities in Qnap Qts

- [CVE-2020-2509](https://insights.sbomify.com/CVE-2020-2509/): QNAP Network-Attached Storage (NAS) Command Injection (critical 9.8, exploited in the wild)
- [CVE-2018-19949](https://insights.sbomify.com/CVE-2018-19949/): QNAP NAS File Station Command Injection (critical 9.8, exploited in the wild)
- [CVE-2019-7193](https://insights.sbomify.com/CVE-2019-7193/): QNAP QTS Improper Input Validation (critical 9.8, exploited in the wild)
- [CVE-2018-19943](https://insights.sbomify.com/CVE-2018-19943/): QNAP NAS File Station Cross-Site Scripting (high 8.0, exploited in the wild)
- [CVE-2018-19953](https://insights.sbomify.com/CVE-2018-19953/): QNAP NAS File Station Cross-Site Scripting (medium 6.1, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-41539 and fix it if it is affected.

What it is: CVE-2026-41539 is a medium-severity cross-site scripting vulnerability in Qnap Qts, published on 9 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-41539 in the wild and no public exploit code.

Affected product: Qnap Qts. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-41539/ (Markdown: https://insights.sbomify.com/CVE-2026-41539/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-41539
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41539
- OSV: https://osv.dev/vulnerability/CVE-2026-41539

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-41539/
Summaries are generated and may contain mistakes; the official description above is the record.