CVE-2026-82758
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.
Scoring
- Severity
- MEDIUM
- CVSS base score
- 6.3
- CVSS 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
- EPSS probability
- 0.38%
- CWE
- CWE-287
- Published
- 2026-09-07
- Last modified
- 2026-09-08
Affected products
- ash-project ash_authentication_oauth2_server
- ash-project ash_authentication_oauth2_server
Weakness type
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