authentik is an open-source Identity Provider. Prior to versions 2025.8.5 and 2025.10.2, when authenticating with client_id and client_secret to an OAuth provider, authentik creates a service account for the provider. In previous authentik versions, authentication for this account was possible even when the account was deactivated. Other permissions are correctly applied and federation with other providers still take assigned policies correctly into account. authentik versions 2025.8.5 and 2025.10.2 fix this issue. A workaround involves adding a policy to the application that explicitly checks if the service account is still valid, and deny access if not.
Weakness
The product performs authentication based on the name of a resource being accessed, or the name of the actor performing the access, but it does not properly check all possible names for that resource or actor.
Affected Software
| Name |
Vendor |
Start Version |
End Version |
| Authentik |
Goauthentik |
2025.8.0 (including) |
2025.8.5 (excluding) |
| Authentik |
Goauthentik |
2025.10.0 (including) |
2025.10.2 (excluding) |
Potential Mitigations
- Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
- Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
References