# CVE-2018-19945: Improper Limitation of a Pathname to a Restricted Directory in QTS

> Attackers can rename arbitrary files on QNAP devices running QTS due to improper pathname restrictions, requiring an upgrade to patched firmware versions.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 31 Dec 2020
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-xc2v-fcxv-wj59

## What is CVE-2018-19945?

CVE-2018-19945 is a critical path traversal vulnerability in Qnap Qts, published on 31 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability has been reported to affect earlier QNAP devices running QTS 4.3.4 to 4.3.6. Caused by improper limitations of a pathname to a restricted directory, this vulnerability allows for renaming arbitrary files on the target system, if exploited. QNAP have already fixed this vulnerability in the following versions: QTS 4.3.6.0895 build 20190328 (and later) QTS 4.3.4.0899 build 20190322 (and later) This issue does not affect QTS 4.4.x or QTS 4.5.x.

Weakness: CWE-73 (External Control of File Name or Path), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-284 (Improper Access Control), CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2018-19945?

It affects 1 product.


Products: Qnap Qts.

## How do I fix CVE-2018-19945?

No fix has been published for CVE-2018-19945 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-19945 being exploited?

There is no known exploitation of CVE-2018-19945 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-2018-19945 and fix it if it is affected.

What it is: CVE-2018-19945 is a critical path traversal vulnerability in Qnap Qts, published on 31 Dec 2020. 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-2018-19945 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-2018-19945/ (Markdown: https://insights.sbomify.com/CVE-2018-19945/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-19945
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-19945
- OSV: https://osv.dev/vulnerability/CVE-2018-19945

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-19945/
Summaries are generated and may contain mistakes; the official description above is the record.