CVE-2026-44476 Doorkeeper OpenID Connect: Dynamic Client Registration feature creates public clients with client_secret
Attackers can authenticate as dynamically registered clients without a secret, bypassing authentication in Doorkeeper OpenID Connect when this feature is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44476?
CVE-2026-44476 is a medium-severity authentication bypass vulnerability in doorkeeper-gem doorkeeper-openid_connect, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Doorkeeper is an OAuth 2 provider for Ruby on Rails. In version 1.9.0, an attacker who knows only a dynamically registered client's client_id, which is public information, can authenticate as that client at the token endpoint and obtain an access token without providing its client_secret. This occurs because the Dynamic Client Registration feature creates applications with confidential: false hard-coded, even though the registration response returns a client_secret and advertises support for the client_secret_basic and client_secret_post authentication methods; since Doorkeeper treats a blank or missing secret as valid for non-confidential (public) clients, the secret is never verified. Only projects that have explicitly enabled Dynamic Client Registration, which is disabled by default, are affected. This issue is fixed in version 1.10.0.
Which versions are affected by CVE-2026-44476?
2 open source packages ship an affected version, including doorkeeper-openid_connect.
| Package | Affected | Fixed in |
|---|---|---|
doorkeeper-openid_connect RubyGems | From 1.9.0 | 1.10.0 |
doorkeeper-openid_connect RubyGems | From 1.9.0 | 1.10.0 |
How do I fix CVE-2026-44476?
Upgrade doorkeeper-openid_connect to 1.10.0 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-44476 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44476 exists.
Sources
Also known as DEBIAN-CVE-2026-44476, GHSA-m6vc-f87m-cc2h, UBUNTU-CVE-2026-44476.