What’s Vulnerable › Vulnerabilities

CVE-2026-40166: authentik: Non-admin user can retrieve confidential OAuth client_secret via /api/v3/oauth2/access_tokens/

• Severity: high (CVSS 7.1 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-22 · updated 2026-07-23
• Weakness: CWE-200

Description

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 products

• goauthentik authentik: before 2025.12.5; from 2026.2.0-rc1, < 2026.2.3

References

• https://github.com/goauthentik/authentik/releases/tag/version%2F2025.12.5
• https://github.com/goauthentik/authentik/releases/tag/version%2F2026.2.3
• https://github.com/goauthentik/authentik/security/advisories/GHSA-hhpc-rqgm-pxj4

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