# CVE-2026-70665 — doorkeeper-gem doorkeeper-openid_connect

> As of 2026-08-25, CVE-2026-70665 is a MEDIUM-severity vulnerability in doorkeeper-gem doorkeeper-openid_connect, CVSS v3.1 4.2, EPSS 0.1% (5.7th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-70665 as of 2026-08-25; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-08-25

## 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](https://intel.threadlinqs.com/cwe/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 2026-08-26. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com](https://github.com/doorkeeper-gem/doorkeeper-openid_connect/security/advisories/GHSA-8r7r-wh7x-27ff)

**Other references**

- [github.com](https://github.com/doorkeeper-gem/doorkeeper-openid_connect/commit/24c3cb1729b69f48649a6f4491dcae69f805000d)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-70665
Full detection coverage and IOCs for threats exploiting CVE-2026-70665 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp