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CVE-2026-40166
Published:May 22, 2026
Updated:June 11, 2026
authentik is an open-source identity provider. In versions prior to 2025.12.5 and 2026.2.0-rc1 through 2026.2.2, authenticated non-admin users with at least one OAuth2 access token can retrieve the client_secret of confidential OAuth2 providers they have previously authenticated against, exposing sensitive information to users without the correct permissions. This logic is GET /api/v3/oauth2/access_tokens/. The API response includes a nested provider object containing client_id and client_secret for providers configured with client_type: confidential, which should not be accessible to low-privilege users. This issue has been fixed in versions 2025.12.5 and 2026.2.3.
Affected Packages
https://github.com/goauthentik/authentik.git (GITHUB):
Affected version(s) >=version/0.0.2-alpha <version/2025.12.5
Fix Suggestion:
Update to version version/2025.12.5
https://github.com/goauthentik/authentik.git (GITHUB):
Affected version(s) >=version/2026.2.0-rc1 <version/2026.2.3
Fix Suggestion:
Update to version version/2026.2.3
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CVSS v4
Base Score:
7.1
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
LOW
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.7
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Weakness Type (CWE)
Exposure of Sensitive Information to an Unauthorized Actor
Incorrect Authorization
EPSS
Base Score:
0.01