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CVE-2026-44476— Doorkeeper OpenID Connect: Dynamic Client Registration feature creates public clients with client_secret

Quick assessment

Affected
doorkeeper-gem doorkeeper-openid_connect
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Doorkeeper 是 Ruby on Rails 的一个 OAuth 2 授权服务器框架。在版本 1.9.0 中，攻击者仅需知道动态注册的客户端的 client_id（该信息为公开），即可在令牌端点（token endpoint）冒充该客户端进行身份验证，并在不提供 client_secret 的情况下获取访问令牌（access token）。 这一漏洞的成因在于：动态客户端注册（Dynamic Client Registration）功能在创建应用时，将 硬编码为固定值，尽管注册响应中返回了 client_s

CVSS 6.3 · Medium EPSS 0.06% · P19

Possible ATT&CK Techniques 1 AI

T1110 · Brute Force
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I. Basic Information for CVE-2026-44476

Vulnerability Information
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Vulnerability Title
Doorkeeper OpenID Connect: Dynamic Client Registration feature creates public clients with client_secret
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
认证机制不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
doorkeeper-gem doorkeeper-openid_connect >= 1.9.0, < 1.10.0 -

II. Public POCs for CVE-2026-44476

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III. Intelligence Information for CVE-2026-44476

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Patches & Fixes for CVE-2026-44476 (1)

Vendor Advisories for CVE-2026-44476 (1)

IV. Related Vulnerabilities

Same product: doorkeeper-openid_connect
Same vendor: doorkeeper-gem
Same weakness: CWE-287

V. Comments for CVE-2026-44476

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