# CVE-2005-4440: Security feature bypass in n/a

> Remote attackers can bypass network segmentation and spoof VLAN traffic by sending double-tagged 802.1q frames, affecting network infrastructure security.

- **Severity:** Medium 5.0 (`AV:N/AC:L/Au:N/C:N/I:P/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Dec 2005
- **Updated:** 7 Aug 2024
- **Also known as:** GHSA-9rvj-pj6p-4pj6

## What is CVE-2005-4440?

CVE-2005-4440 is a medium-severity vulnerability in n/a, published on 21 Dec 2005. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The 802.1q VLAN protocol allows remote attackers to bypass network segmentation and spoof VLAN traffic via a message with two 802.1q tags, which causes the second tag to be redirected from a downstream switch after the first tag has been stripped, as demonstrated by Yersinia, aka "double-tagging VLAN jumping attack."

## Which versions are affected by CVE-2005-4440?

It affects 1 product.


Products: Vlan Protocol Vlan Protocol.

## How do I fix CVE-2005-4440?

No fix has been published for CVE-2005-4440 yet. Limit exposure of the affected software until one is available.

## Is CVE-2005-4440 being exploited?

There is no known exploitation of CVE-2005-4440 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2005-4440 and fix it if it is affected.

What it is: CVE-2005-4440 is a medium-severity vulnerability in n/a, published on 21 Dec 2005. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2005-4440 in the wild and no public exploit code.

Affected product: n/a. 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-2005-4440/ (Markdown: https://insights.sbomify.com/CVE-2005-4440/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2005-4440
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2005-4440
- OSV: https://osv.dev/vulnerability/CVE-2005-4440

---
From sbomify Insights: https://insights.sbomify.com/CVE-2005-4440/
Summaries are generated and may contain mistakes; the official description above is the record.