vulnerability / NVI-00018320 / Revision 1
@yoda.digital/gitlab-mcp-server's SSE transport has no authentication and wildcard CORS, exposing all 86 GitLab tools
GitHub lists this reviewed advisory for @yoda.digital/gitlab-mcp-server. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
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02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
@yoda.digital/gitlab-mcp-server
source listed< 0.6.0
## SSE Transport Has No Authentication and Wildcard CORS, Exposing All 86 GitLab Tools Including Destructive Operations A review of `mcp-gitlab-server` at commit `80a7b4cf3fba6b55389c0ef491a48190f7c8996a` uncovered that the SSE HTTP transport — advertised in the README and comparison table as a differentiating feature — runs with no authentication and wildcard CORS on every endpoint. The maintainers' own roadmap confirms auth is a known gap. When `USE_SSE=true`, the HTTP server in `src/transport.ts` sets: ```typescript res.setHeader('Access-Control-Allow-Origin', '*'); res.setHeader('Access-Control-Allow-Methods', 'GET, POST'); res.setHeader('Access-Control-Allow-Headers', 'Content-Type'); ``` The `httpServer.listen(port)` call at line 97 passes no host argument — Node.js defaults to `0.0.0.0`, binding on all interfaces. Two endpoints are exposed with no credential check: - `GET /sse` — opens an SSE connection, returns a session endpoint URL - `POST /messages?sessionId=` — sends MCP messages to the server using the loaded `GITLAB_PERSONAL_ACCESS_TOKEN` Any caller who can reach the port — LAN, cloud instance, or via the browser-tab vector the wildcard CORS enables — gets f
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-8jr5-6gvj-rfpf ↗
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- Revision 1 ·
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