# CVE-2026-22320: Stack-Based Buffer Overflow in TFTP File-Transfer Command Handling over CLI

> A low-privileged attacker can cause a denial of service by triggering a stack-based buffer overflow in the CLI's TFTP command handling.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Mar 2026
- **Updated:** 18 Mar 2026
- **Also known as:** GHSA-22m2-mv56-5hwq

## What is CVE-2026-22320?

CVE-2026-22320 is a medium-severity memory corruption vulnerability in Phoenix Contact FL NAT 2008, published on 18 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A stack-based buffer overflow in the CLI's TFTP file‑transfer command handling allows a low-privileged attacker with Telnet/SSH access to trigger memory corruption by supplying unexpected or oversized filename input. Exploitation results in the corruption of the internal buffer, causing the CLI and web dashboard to become unavailable and leading to a denial of service.

Weakness: CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2026-22320?


## How do I fix CVE-2026-22320?

No fix has been published for CVE-2026-22320 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-22320 being exploited?

There is no known exploitation of CVE-2026-22320 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-22320 and fix it if it is affected.

What it is: CVE-2026-22320 is a medium-severity memory corruption vulnerability in Phoenix Contact FL NAT 2008, published on 18 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-22320 in the wild and no public exploit code.

Affected product: Phoenix Contact FL NAT 2008. 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-2026-22320/ (Markdown: https://insights.sbomify.com/CVE-2026-22320/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22320
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22320
- OSV: https://osv.dev/vulnerability/CVE-2026-22320

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-22320/
Summaries are generated and may contain mistakes; the official description above is the record.