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.
- 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
- None listed
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
Which versions are affected by CVE-2026-43901?
3 open source packages ship an affected version, including wireshark-mcp. It affects 1 product.
| Package | 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 include 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.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-43901 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43901 exists.
Sources
Also known as GHSA-3r68-x3xc-rxpg, PYSEC-2026-3426, UBUNTU-CVE-2026-43901.