CVE-2023-48228
OAuth2: PKCE can be fully circumvented
Description
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.
How to fix CVE-2023-48228
To remediate CVE-2023-48228, upgrade the affected package to a fixed version below.
- —upgrade to 2023.8.5 or later
Is CVE-2023-48228 being exploited?
Low — EPSS is 1.1%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 2023.8.5, >= 2023.10.0, < 2023.10.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |