Security 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 64th percentile
Risk Priority 46 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

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 Data Obfuscation (T1001); ranked in the top 36% 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)
CWE-625

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001 Data Obfuscation Command And Control
Adversaries may obfuscate command and control traffic to make it more difficult to detect.
attack.mitre.org →
T1001.002 Steganography Command And Control
Adversaries may use steganographic techniques to hide command and control traffic to make detection efforts more difficult.
attack.mitre.org →
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
attack.mitre.org →
T1003.005 Cached Domain Credentials Credential Access
Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.
attack.mitre.org →
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
T1007 System Service Discovery Discovery
Adversaries may try to gather information about registered local system services.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-14814Shared CWE-625
CVE-2026-64940Shared CWE-625
CVE-2026-34830Shared CWE-625
CVE-2026-34763Shared CWE-625
CVE-2026-23651Shared CWE-625
CVE-2026-32973Shared CWE-625
CVE-2026-37737Shared CWE-625
CVE-2026-55536Shared CWE-625
CVE-2026-40110Shared CWE-625
CVE-2026-83609Shared CWE-625

Affected Assets

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation partial match

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 partial match
blocks

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.

A.7.9 Security of assets off-premises partial match
removes
A.8.25 Secure development life cycle partial match
blocks

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

A.8.26 Application security requirements partial match
blocks

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

A.8.27 Secure system architecture and engineering principles partial match
removes
A.8.28 Secure coding partial match
prevents

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

A.8.29 Security testing in development and acceptance partial match
finds

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

References