CVE-2023-6544Network attack vector

Unauthorized client registration via permissive trusted-domain regex

Published Apr 25, 2024 · Updated Nov 11, 2025

Authorization bypass in Keycloak 22.0.0 through 22.0.9 and 23.0.0 through 24.0.2 allows remote authenticated users to register clients. A permissive hardcoded regular expression in TrustedDomain host filtering treats an unauthorized requesting host as trusted. Reachability requires Dynamic Client Registration with a TrustedDomain policy and enough environment knowledge to craft the host value, resulting in unauthorized client registration.

CVSS severity5.4
Medium
EPSS probability1.07%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization bypass in Keycloak 22.0.0 through 22.0.9 and 23.0.0 through 24.0.2 allows remote authenticated users to register clients. A permissive hardcoded regular expression in TrustedDomain host filtering treats an unauthorized requesting host as trusted. Reachability requires Dynamic Client Registration with a TrustedDomain policy and enough environment knowledge to craft the host value, resulting in unauthorized client registration.

The record

CVE
CVE-2023-6544
Published
Apr 25, 2024
Updated
Nov 11, 2025
Vendor
Red Hat
Product
RHEL-8 based Middleware Containers
Classifications
CWE-625
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 25, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 11, 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?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Red Hat · RHEL-8 based Middleware ContainersAffected versions are unavailable in this record.
389 Directory Server · Red Hat Single Sign-OnAffected versions are unavailable in this record.
Red Hat · Red Hat build of Keycloak 22Affected versions are unavailable in this record.
Keycloak · Keycloakversion=22.0.0 <22.0.10; version=23.0.0 <24.0.3

Published CVSS scores

5.4Red HatCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-625Permissive Regular Expression

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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