Description
Improper Authentication vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to register OAuth clients even when Dynamic Client Registration is gated by an initial access token.

resolve_secret/3 in AshAuthentication.Oauth2Server (reached through __resolve_secret__!) treated any return other than {:ok, _} or :error from a configured {module, function, args} or 2-arity-function secret provider as a valid secret, wrapping nil, false, or "" as {:ok, value}. When the initial_access_token resolves to such an empty value, POST /oauth/register compares the presented bearer token against it and the comparison passes with no token supplied, so registration is open although it was configured closed. The same fail-open affected other resolved secrets such as signing_secret.

This issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1.
Published: 2026-09-07
Score: 6.3 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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History

Tue, 08 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 07 Sep 2026 22:45:00 +0000

Type Values Removed Values Added
Description Improper Authentication vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to register OAuth clients even when Dynamic Client Registration is gated by an initial access token. resolve_secret/3 in AshAuthentication.Oauth2Server (reached through __resolve_secret__!) treated any return other than {:ok, _} or :error from a configured {module, function, args} or 2-arity-function secret provider as a valid secret, wrapping nil, false, or "" as {:ok, value}. When the initial_access_token resolves to such an empty value, POST /oauth/register compares the presented bearer token against it and the comparison passes with no token supplied, so registration is open although it was configured closed. The same fail-open affected other resolved secrets such as signing_secret. This issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1.
Title ash_authentication_oauth2_server treats an empty resolved secret as valid, opening the gated Dynamic Client Registration endpoint
First Time appeared Ash-project
Ash-project ash Authentication Oauth2 Server
Weaknesses CWE-287
CPEs cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*
Vendors & Products Ash-project
Ash-project ash Authentication Oauth2 Server
References
Metrics cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N'}


Subscriptions

Ash-project Ash Authentication Oauth2 Server
cve-icon MITRE

Status: PUBLISHED

Assigner: EEF

Published:

Updated: 2026-09-08T14:41:06.227Z

Reserved: 2026-08-31T01:00:10.817Z

Link: CVE-2026-82758

cve-icon Vulnrichment

Updated: 2026-09-08T14:41:01.131Z

cve-icon NVD

Status : Deferred

Published: 2026-09-07T23:16:53.123

Modified: 2026-09-08T15:18:50.977

Link: CVE-2026-82758

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-08T02:00:19Z

Weaknesses