What is CVE-2026-70665?
Doorkeeper OpenID Connect implements an OpenID Connect authentication provider for Rails applications on top of Doorkeeper. Prior to 1.10.4, the Dynamic Client Registration (DCR) endpoint persists client-supplied scopes without validating them against the server's configured scope set. Under certain conditions, this allows a self-registered client to obtain scopes beyond what the server intended to grant. In DynamicClientRegistrationController#application_params, the scopes attribute is assigned directly from params[:scope] with no validation against Doorkeeper.configuration.scopes or optional_scopes. Combined with enforce_configured_scopes being off by default and Doorkeeper's ScopeChecker prioritizing application-level scopes over server-level scopes, this creates a privilege escalation path. This issue is fixed in version 1.10.4.
The record classifies CVE-2026-70665 under weakness class CWE-285. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs a user to take an action first. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 41 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 4.2 — MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N - EPSS (FIRST)
- 0.1% probability of exploitation in the next 30 days, higher than 5.7% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 2.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-08-25
Is CVE-2026-70665 being exploited?
It currently carries a trending score of 31 in the Threadlinqs vulnerability feed.
Affected products and versions
- doorkeeper-gem: doorkeeper-openid_connect
How to fix CVE-2026-70665
No vendor patch reference has been recorded for CVE-2026-70665 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-70665
No threat campaign in the Threadlinqs corpus currently references CVE-2026-70665, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.