# CVE-2026-20018: Cisco Firepower Management Center Software and Firepower Threat Defense Path Traversal Vulnerability

> Authenticated administrators can exploit path traversal in Cisco FMC and FTD to write arbitrary files as root, potentially leading to code execution.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Mar 2026
- **Updated:** 4 Mar 2026
- **Also known as:** GHSA-6jcc-w84h-p298

## What is CVE-2026-20018?

CVE-2026-20018 is a medium-severity path traversal vulnerability in Cisco Secure Firewall Management Center (FMC), published on 4 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

A vulnerability in the sftunnel functionality of Cisco Secure Firewall Management Center (FMC) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker with administrative privileges to write arbitrary files as root on the underlying operating system.

This vulnerability is due to insufficient validation of the directory path during file synchronization. An attacker could exploit this vulnerability by crafting a directory path outside of the expected file location. A successful exploit could allow the attacker to create or replace any file on the underlying operating system.

Weakness: CWE-27 (Path Traversal: 'dir/../../filename')

## Which versions are affected by CVE-2026-20018?


## How do I fix CVE-2026-20018?

No fix has been published for CVE-2026-20018 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-20018 being exploited?

There is no known exploitation of CVE-2026-20018 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-20018 and fix it if it is affected.

What it is: CVE-2026-20018 is a medium-severity path traversal vulnerability in Cisco Secure Firewall Management Center (FMC), published on 4 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-20018 in the wild and no public exploit code.

Affected product: Cisco Secure Firewall Management Center (FMC). 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-2026-20018/ (Markdown: https://insights.sbomify.com/CVE-2026-20018/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20018
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20018
- OSV: https://osv.dev/vulnerability/CVE-2026-20018

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-20018/
Summaries are generated and may contain mistakes; the official description above is the record.