Obot: MCP Registry API readable without authentication

In affected versions, enabling registry authentication (OBOT_SERVER_ENABLE_REGISTRY_AUTH=true) does not actually protect the MCP Registry endpoints under /v0.1/* — they remain readable by unauthenticated callers.

Am I affected?

You are affected if you run Obot <= v0.22.1 with OBOT_SERVER_ENABLE_REGISTRY_AUTH=true. An unauthenticated GET /v0.1/servers returns 200 OK with catalog server metadata. (With registry auth disabled, the registry is intentionally public and this is not a defect.)

Details

The authorizer rejects a fixed set of known-protected prefixes and then default-allows everything else. The registry is mounted at the top-level /v0.1 prefix, which was not in that set, so anonymous requests were authorized before the WWW-Authenticate challenge for /v0.1 was ever reached. The registry handler still applies its own per-user ACR filtering, so an anonymous caller receives only entries accessible to the anonymous identity (e.g. default-catalog/wildcard entries), and responses contain names, descriptions, repository URLs, icons, and connect URLs — not secret env/header values. This is the same root cause as GHSA-vw82-7fv8-r6gp, whose fix protected /mcp-connect/ but not the /v0.1 registry prefix.

Impact

Worst case is disclosure of the registry server inventory (names, descriptions, repository URLs, connect URLs) that the operator explicitly chose to put behind authentication. No credential values are exposed and unauthenticated users cannot connect to the servers because connecting is properly protected by auth.

Mitigation

Upgrade to v0.23.0 or later, in which the /v0.1 registry prefix is treated as a protected route so authentication is enforced for unauthenticated callers.

Severity

CVSS v3.1 Score: 5.3/10 (Medium) — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Credits

The Obot team would like to thank HE WEI（ギカク）(https://www.linkedin.com/in/gikaku, @hewei-gikaku) for responsibly disclosing this issue in accordance with our security policy.