CVE-2024-23647Network attack vector

Authorization-code injection via PKCE challenge removal

Published Jan 30, 2024 · Updated Jun 17, 2025

PKCE downgrade in Authentik before 2023.8.7 and 2023.10.0 through 2023.10.6 allows remote attackers to inject OAuth authorization codes. The OAuth2 token handler accepted a code_verifier when the stored authorization code had no code_challenge, so removal of the challenge went undetected. Exploitation requires a user to follow an attacker-controlled authorization link, and the resulting code injection defeats PKCE integrity protection.

CVSS severity6.5
Medium
EPSS probability0.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

PKCE downgrade in Authentik before 2023.8.7 and 2023.10.0 through 2023.10.6 allows remote attackers to inject OAuth authorization codes. The OAuth2 token handler accepted a code_verifier when the stored authorization code had no code_challenge, so removal of the challenge went undetected. Exploitation requires a user to follow an attacker-controlled authorization link, and the resulting code injection defeats PKCE integrity protection.

The record

CVE
CVE-2024-23647
Published
Jan 30, 2024
Updated
Jun 17, 2025
Vendor
Authentik Security Inc.
Product
authentik
Classifications
CWE-287, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 30, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 2023.10.0, < 2023.10.7
  2. Affected versionversion=< 2023.8.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Authentik Security Inc. · authentikversion=>= 2023.10.0, < 2023.10.7; version=< 2023.8.7

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1204.001User Execution: Malicious Link

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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