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CVE-2026-44476 doorkeeper-gem CVE debrief

CVE-2026-44476 is a vulnerability in Doorkeeper, an OAuth 2 provider for Ruby on Rails. A dynamically registered client's client_id can be used to authenticate at the token endpoint without providing its client_secret, due to the confidential: false setting. This issue is fixed in version 1.10.0. The vulnerability allows an attacker who knows only a dynamically registered client's client_id, which is public information, to authenticate as that client and obtain an access token. 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

Vendor
doorkeeper-gem
Product
doorkeeper-openid_connect
CVSS
MEDIUM 6.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-25
Original CVE updated
2026-09-09
Advisory published
2026-08-25
Advisory updated
2026-09-09

Who should care

Ruby on Rails developers using Doorkeeper version 1.9.0 with Dynamic Client Registration enabled should assess exposure, verify upgrade to version 1.10.0, and review client configurations for confidential: false setting. Defenders should prioritize verifying authentication mechanisms for Doorkeeper clients and evaluating the impact of the vulnerability on their systems.

Why it matters

CVE-2026-44476 allows authentication bypass in Doorkeeper version 1.9.0; defenders should assess exposure, verify upgrade, and review client configurations.

  • Verify authentication mechanisms for Doorkeeper clients
  • Assess exposure to unauthorized access
  • Evaluate upgrade to version 1.10.0
  • Review client configurations for confidential: false setting

Technical summary

Doorkeeper version 1.9.0 vulnerable to authentication bypass due to confidential: false setting in Dynamic Client Registration. The vulnerability allows an attacker to authenticate as a dynamically registered client without providing its client_secret. This issue is fixed in version 1.10.0. Only projects that have explicitly enabled Dynamic Client Registration are affected. The confidential: false setting is hard-coded in the Dynamic Client Registration feature, despite the registration response returning a client_secret.

Defensive priority

Assess exposure if using Doorkeeper version 1.9.0 with Dynamic Client Registration enabled; verify upgrade to version 1.10.0.

Recommended defensive actions

  • Assess exposure if using Doorkeeper version 1.9.0 with Dynamic Client Registration enabled
  • Verify upgrade to version 1.10.0
  • Review client configurations for confidential: false setting
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
  • Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and NVD entry provide details on the vulnerability and its fix. Doorkeeper version 1.9.0 is affected when Dynamic Client Registration is enabled. The issue allows authentication bypass, potentially leading to unauthorized access. Defenders should verify the upgrade to version 1.10.0 and review client configurations for confidential: false setting. Evidence from the CVE record indicates that only projects with explicitly enabled Dynamic Client Registration are affected.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-44476 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-44476

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-44476 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-44476

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.