OAuth2: PKCE can be fully circumvented
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-287.
Summary
authentik is an open-source identity provider. When initialising a oauth2 flow with a `code_challenge` and `code_method` (thus requesting PKCE), the single sign-on provider (authentik) must check if there is a matching and existing `code_verifier` during the token step. Prior to versions 2023.10.4 and 2023.8.5, authentik checks if the contents of `code_verifier` is matching only when it is provided. When it is left out completely, authentik simply accepts the token request with out it; even when the flow was started with a `code_challenge`. authentik 2023.8.5 and 2023.10.4 fix this issue.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| goauthentik | authentik | before 2023.10.4; before 2023.8.5 | 2023.10.4, 2023.8.5 | Patch available | CNA |
- authentik Vendorgoauthentik Affected before 2023.10.4; before 2023.8.5 Fixed in 2023.10.4, 2023.8.5 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:goauthentik:authentik:*:*:*:*:*:*:*:* | before 2023.8.5; 2023.10.0 to before 2023.10.4 | Vulnerable | goauthentik |
- cpe:2.3:a:goauthentik:authentik:*:*:*:*:*:*:*:* Versions before 2023.8.5; 2023.10.0 to before 2023.10.4 Vulnerable ·goauthentik
Remediation
- Fix · CNA authentik (goauthentik) Fixed in 2023.10.4, 2023.8.5
Timeline
- 2026-10-02 Threatist record created from CVE-2023-48228
References
Patch 6
- https://github.com/goauthentik/authentik/pull/7666
- https://github.com/goauthentik/authentik/pull/7668
- https://github.com/goauthentik/authentik/pull/7669
- https://github.com/goauthentik/authentik/commit/3af77ab3821fe9c7df8055ba5eade3d1ecea03a6
- https://github.com/goauthentik/authentik/commit/6b9afed21f7c39f171a4a445654cfe415bba37d5
- https://github.com/goauthentik/authentik/commit/b88e39411c12e3f9e04125a7887f12354f760a14
More goauthentik Authentik vulnerabilities
- TI-2026-36603 authentik: SourceStage bypass via empty POST CVSS 3.1CRITICAL 9.8
- TI-2022-07608 authentik vulnerable to Improper Authentication via invitation URL token reuse CVSS 3.1CRITICAL 9.4
- TI-2026-36598 authentik: `UserSourceConnection.user` and `GroupSourceConnection.group` are changeable through the API CVSS 3.1HIGH 8.8
- TI-2022-22816 authentik allows existing authenticated users to create arbitrary accounts CVSS 3.1MEDIUM 6.4
- TI-2024-25628 Insufficient access control for OAuth2 Device Code flow in authentik CVSS 3.1CRITICAL 9.8
- TI-2023-24876 authentik potential installation takeover when default admin user is deleted CVSS 3.1CRITICAL 9.8
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences