CVE-2023-48228 — authentik is an open-source identity provider

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

01What is this vulnerability?

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…

02Affected products

Vendor	Product	Versions
goauthentik	authentik	< 2023.10.4, < 2023.8.5

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-11-21T20:48:32.552Z
• Last modified: 2024-08-02T21:23:39.088Z

09References

• github.com — https://github.com/goauthentik/authentik/security/advisories/GHSA-fm34-v8xq-f2c3
• github.com — https://github.com/goauthentik/authentik/pull/7666
• github.com — https://github.com/goauthentik/authentik/pull/7668
• github.com — https://github.com/goauthentik/authentik/pull/7669
• github.com — https://github.com/goauthentik/authentik/commit/3af77ab3821fe9c7df8055ba5eade3d1…
• github.com — https://github.com/goauthentik/authentik/commit/6b9afed21f7c39f171a4a445654cfe41…
• github.com — https://github.com/goauthentik/authentik/commit/b88e39411c12e3f9e04125a7887f1235…
• github.com — https://github.com/goauthentik/authentik/blob/dd4e9030b4e667d3720be2feda24c08972…
• github.com — https://github.com/goauthentik/authentik/releases/tag/version%2F2023.10.4
• github.com — https://github.com/goauthentik/authentik/releases/tag/version%2F2023.8.5