# 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.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 17 Sep 2026
- **Also known as:** GHSA-6f5r-5672-72j7

## 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.

Weakness: CWE-668 (Exposure of Resource to Wrong Sphere), CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-54504?

2 open source packages ship an affected version, including @andrea9293/mcp-documentation-server.


| Package | Ecosystem | 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.

## Is CVE-2026-54504 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54504 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54504 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54504 exists.

Affected packages and fixed versions:
- @andrea9293/mcp-documentation-server (npm): affected from 1.13.0; fixed in 1.13.1
- @andrea9293/mcp-documentation-server (npm): affected from 1.13.0; fixed in 1.13.1

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-2026-54504/ (Markdown: https://insights.sbomify.com/CVE-2026-54504/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54504
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54504
- OSV: https://osv.dev/vulnerability/CVE-2026-54504

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-54504/
Summaries are generated and may contain mistakes; the official description above is the record.