CVE-2026-54504 MCP Documentation Server: Web UI API binds to all interfaces without authentication by default
Unauthenticated network access allows attackers to read, search, insert, and delete documents in the MCP Documentation Server knowledge base.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-54504?
CVE-2026-54504 is a high-severity missing authorization vulnerability in andrea9293 mcp-documentation-server, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
MCP Documentation Server is a local-first document management and semantic search server for AI coding agents. From 1.13.0 until 1.13.1, the automatically started Web UI in src/server.ts calls startWebServer in src/web-server.ts with START_WEB_UI enabled by default and WEB_PORT set to 3080. startWebServer uses app.listen(PORT) without a host, which binds the unauthenticated document-management API to all interfaces rather than localhost. A network-reachable client can invoke GET /api/documents, GET /api/documents/:id, POST /api/documents, POST /api/search-all, DELETE /api/documents/:id, and GET /api/config without credentials to enumerate and read documents, search the corpus, insert or delete documents, and tamper with the MCP assistant's knowledge base. The service must be reachable from the attacker's LAN, VM network, container bridge, VPN, or another routed network, and the issue does not provide remote code execution. This issue is fixed in 1.13.1.
Which versions are affected by CVE-2026-54504?
2 open source packages ship an affected version, including @andrea9293/mcp-documentation-server.
| Package | Affected | Fixed in |
|---|---|---|
@andrea9293/mcp-documentation-server npm | From 1.13.0 | 1.13.1 |
@andrea9293/mcp-documentation-server npm | From 1.13.0 | 1.13.1 |
How do I fix CVE-2026-54504?
Upgrade @andrea9293/mcp-documentation-server to 1.13.1 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-54504 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54504 exists.
Sources
Also known as GHSA-6f5r-5672-72j7.