Description
GitLab MCP Server lets an AI agent talk directly to GitLab. Prior to 0.6.0, the HTTP transport in src/transport.ts ships with no authentication layer at all and a wildcard Access-Control-Allow-Origin: * on every response. The structural defect is that the SSE server stands up a stateful, mutation-capable RPC endpoint that is backed by the operator's GITLAB_PERSONAL_ACCESS_TOKEN without any inbound credential check, then advertises itself to every cross-origin browser context via the wildcard CORS header. The httpServer.listen(port) call at line 97 also passes no host argument, so the bind defaults to 0.0.0.0 and exposes the auth-less surface on every interface. This vulnerability is fixed in 0.6.0.
Problem types
CWE-306: Missing Authentication for Critical Function
CWE-942: Permissive Cross-domain Policy with Untrusted Domains
Product status
References
github.com/...server/security/advisories/GHSA-8jr5-6gvj-rfpf
github.com/...server/security/advisories/GHSA-8jr5-6gvj-rfpf