OAuth 2 Vulnerability in Doorkeeper for Ruby on Rails
CVE-2026-44476

6.3MEDIUM

Key Information:

Vendor

Doorkeeper-gem

Status
Doorkeeper-openid Connect
Vendor
CVE Published:
25 August 2026

What is CVE-2026-44476?

In Doorkeeper version 1.9.0, a security vulnerability exists that allows an attacker to authenticate as a dynamically registered client at the token endpoint using only the client_id, without needing the client_secret. This occurs due to the Dynamic Client Registration feature which defaults clients to non-confidential status, rendering the absence of a client_secret valid for authentication. This issue specifically affects projects where Dynamic Client Registration has been enabled, which is not the default setting. The flaw has been addressed in version 1.10.0.

Affected Version(s)

doorkeeper-openid_connect >= 1.9.0, < 1.10.0

References

https://github.com/doorkeeper-gem/doorkeeper-openid_conne...
x_refsource_CONFIRM
https://github.com/doorkeeper-gem/doorkeeper-openid_conne...
x_refsource_MISC

CVSS V4

Score:
6.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.