Cyber Resilience

CVE-2023-6544

Published
25 April 2024
Modified
15 April 2026
CVSS Score v3.1 5.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
EPSS Score 0.011 62th percentile
Risk Priority 46 floored blend · peak EPSS

Summary

CVE-2023-6544 is a medium-severity Permissive Regular Expression (CWE-625) vulnerability. Its CVSS base score is 5.4 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 38% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A flaw was found in the Keycloak package. This issue occurs due to a permissive regular expression hardcoded for filtering which allows hosts to register a dynamic client. A malicious user with enough information about the environment could jeopardize an…

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environment with this specific Dynamic Client Registration and TrustedDomain configuration previously unauthorized.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-34763Shared CWE-625
CVE-2026-64940Shared CWE-625
CVE-2026-34830Shared CWE-625
CVE-2026-23651Shared CWE-625
CVE-2026-32973Shared CWE-625
CVE-2026-40110Shared CWE-625
CVE-2026-37737Shared CWE-625
CVE-2026-44587Shared CWE-625

Affected Assets

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SI-10 requires validity checks on inputs, directly stopping permissive regex patterns from being used for validation.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require robust input-validation regex and testing that would prevent permissive patterns.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can detect permissive regex through fuzzing or negative test cases.

prevents

Secure development lifecycle requires validation of input mechanisms, including regex, reducing permissive patterns.

prevents

Application security requirements mandate strict input validation rules that would catch overly permissive regex.

prevents

Secure coding standards directly prohibit permissive regex and enforce strict pattern validation.

References