CVE-2024-23647 PKCE downgrade attack in Authentik

2024-01-3016:10:55

CWE-287

GitHub_M

www.cve.org

cve-2024-23647

pkce downgrade

authentik

identity provider

csrf attacks

code injection

bug fix

6.5 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

0.001 Low

EPSS

Percentile

39.3%

JSON

Authentik is an open-source Identity Provider. There is a bug in our implementation of PKCE that allows an attacker to circumvent the protection that PKCE offers. PKCE adds the code_challenge parameter to the authorization request and adds the code_verifier parameter to the token request. Prior to 2023.8.7 and 2023.10.7, a downgrade scenario is possible: if the attacker removes the code_challenge parameter from the authorization request, authentik will not do the PKCE check. Because of this bug, an attacker can circumvent the protection PKCE offers, such as CSRF attacks and code injection attacks. Versions 2023.8.7 and 2023.10.7 fix the issue.

CNA Affected

[
  {
    "vendor": "goauthentik",
    "product": "authentik",
    "versions": [
      {
        "version": "< 2023.8.7",
        "status": "affected"
      },
      {
        "version": ">= 2023.10.0, < 2023.10.7",
        "status": "affected"
      }
    ]
  }
]