# CVE-2025-66277: QTS, QuTS hero

> Remote attackers can exploit a link following vulnerability to traverse the file system and access unintended locations on QNAP NAS devices.

- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 Feb 2026
- **Updated:** 26 Feb 2026
- **Also known as:** GHSA-3wh2-2wc5-f45w

## What is CVE-2025-66277?

CVE-2025-66277 is a critical path traversal vulnerability in Qnap Qts, published on 11 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A link following vulnerability has been reported to affect several QNAP operating system versions. The remote attackers can then exploit the vulnerability to traverse the file system to unintended locations.

We have already fixed the vulnerability in the following versions:
QTS 5.2.8.3350 build 20251216 and later
QuTS hero h5.3.2.3354 build 20251225 and later
QuTS hero h5.2.8.3350 build 20251216 and later

Weakness: CWE-59 (Improper Link Resolution Before File Access)

## Which versions are affected by CVE-2025-66277?

It affects 2 products.


Products: Qnap Qts, Qnap Quts Hero.

## How do I fix CVE-2025-66277?

No fix has been published for CVE-2025-66277 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-66277 being exploited?

There is no known exploitation of CVE-2025-66277 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-2025-66277 and fix it if it is affected.

What it is: CVE-2025-66277 is a critical path traversal vulnerability in Qnap Qts, published on 11 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-66277 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-2025-66277/ (Markdown: https://insights.sbomify.com/CVE-2025-66277/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-66277
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-66277
- OSV: https://osv.dev/vulnerability/CVE-2025-66277

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-66277/
Summaries are generated and may contain mistakes; the official description above is the record.