8.8

CVE-2024-23647: PKCE downgrade attack in Authentik

Modified
AliasesGHSA-mrx3-gxjx-hjqjBIT-authentik-2024-23647GO-2024-2479
Published 30-01-2024Last modified 17-06-2025

Vulnerability summary

CVE-2024-23647 is a high (CVSS 8.8) Improper Authentication vulnerability in goauthentik authentik. EPSS estimates a 0.55% chance of exploitation in the next 30 days, higher than 45.9% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6.5, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
8.8/10
010
High · v3.1 (NVD)
EPSS score
0.55%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 30-01-2024
    PublishedVulnerability first disclosed.
  2. 17-06-2025
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.55%

Chance of exploitation in the next 30 days

Percentile

46%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.54% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.

Go1 product
  • goauthentik.io≥ 2023.10.0, < 2023.10.7 | < 2023.8.7 | All versions (No fix recorded)
Goauthentik1 product
  • authentik< 2023.8.7 | ≥ 2023.10.0, < 2023.10.7

2 vendors · 2 products

References

4 links