# CVE-2026-43901: Wireshark MCP: Arbitrary file write via export_objects when WIRESHARK_MCP_ALLOWED_DIRS is not configured

> Attackers can write arbitrary files to the filesystem via the export_objects tool in default installations of Wireshark MCP.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 11 May 2026
- **Updated:** 13 May 2026
- **Also known as:** GHSA-3r68-x3xc-rxpg, PYSEC-2026-3426, UBUNTU-CVE-2026-43901

## What is CVE-2026-43901?

CVE-2026-43901 is a medium-severity path traversal vulnerability in bx33661 Wireshark-MCP, published on 11 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Wireshark MCP is an MCP Server that turns tshark into a structured analysis interface, then layers in optional Wireshark suite utilities. In 1.1.5 and earlier, wireshark-mcp exposes a wireshark_export_objects MCP tool that accepts an attacker-controlled dest_dir parameter and passes it to tshark's --export-objects flag with no mandatory path restriction. The path sandbox (_allowed_dirs) is None by default and only activates when the environment variable WIRESHARK_MCP_ALLOWED_DIRS is explicitly set. In a default installation, any directory on the filesystem can be used as the export destination.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-43901?

3 open source packages ship an affected version, including wireshark-mcp. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `wireshark-mcp` | PyPI | All versions to 1.1.5 | None |
| `wireshark-mcp` | PyPI | All versions to 1.1.5 | None |
| `wireshark-mcp` | PyPI | All versions to 1.1.5 | None |

Products: Bx33661 Wireshark Mcp.

## How do I fix CVE-2026-43901?

No fix has been published for CVE-2026-43901 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-43901 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43901 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43901 and fix it if it is affected.

What it is: CVE-2026-43901 is a medium-severity path traversal vulnerability in bx33661 Wireshark-MCP, published on 11 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43901 exists.

Affected packages and fixed versions:
- wireshark-mcp (PyPI): affected all versions up to 1.1.5; no fix listed
- wireshark-mcp (PyPI): affected all versions up to 1.1.5; no fix listed
- wireshark-mcp (PyPI): affected all versions up to 1.1.5; no fix listed

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-2026-43901/ (Markdown: https://insights.sbomify.com/CVE-2026-43901/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43901
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43901
- OSV: https://osv.dev/vulnerability/CVE-2026-43901

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43901/
Summaries are generated and may contain mistakes; the official description above is the record.