vulnerability / NVI-00018368 / Revision 1
Doorkeeper Openid Connect: Dynamic Client Registration feature creates public clients with client_secret
GitHub lists this reviewed advisory for doorkeeper-openid_connect. 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
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
doorkeeper-openid_connect
source listed= 1.9.0
### Impact The `DynamicClientRegistrationController#register` action hard-codes `confidential: false` when creating applications (dynamic_client_registration_controller.rb:18-25), yet the response includes a client_secret and advertises `token_endpoint_auth_methods_supported: ["client_secret_basic", "client_secret_post"]`. Because Doorkeeper's `Application.by_uid_and_secret` treats a blank/missing secret as valid for non-confidential (public) clients, an attacker who knows only the client_id (which is public information) can authenticate as the dynamically-registered client at the token endpoint. **Note** that Dynamic Client Registration is opt-in feature which is disabled by default so only projects that explicitly enabled it are affected. **Steps to Reproduce** 1. Enable dynamic client registration in the initializer 2. POST /oauth/registration with client_name, redirect_uris, and scope 3. Observe: response returns client_secret, but the created Doorkeeper::Application has confidential: false 4. Call `Doorkeeper::Application.by_uid_and_secret(client_id, nil)` — it returns the application (credentials bypass) 5. POST /oauth/token with grant_type=client_credentials and only cl
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
A fixed release is not deployment evidence.
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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-m6vc-f87m-cc2h ↗
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Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.