Cyber Resilience

CVE-2025-54001

CriticalRCE

Published: 05 March 2026

Published
05 March 2026
Modified
22 April 2026
KEV Added
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Patch
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CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0051 39.5th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2025-54001 is a critical-severity Deserialization of Untrusted Data (CWE-502) vulnerability. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 39.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Deeper analysis

CVE-2025-54001 is a Deserialization of Untrusted Data vulnerability (CWE-502) in the ThemeREX Classter WordPress theme that enables PHP Object Injection. Published on 2026-03-05, this issue affects Classter versions from n/a through 2.5.

The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating it can be exploited remotely by unauthenticated attackers with low attack complexity and no user interaction required. Successful exploitation could result in high impacts to confidentiality, integrity, and availability, such as arbitrary code execution depending on the deserialized objects.

Mitigation details are available in the Patchstack advisory at https://patchstack.com/database/Wordpress/Theme/classter/vulnerability/wordpress-classter-theme-2-5-php-object-injection-vulnerability?_s_id=cve.

OWASP Top 10 for Web (2025)

A08:2025 Software or Data Integrity Failures

EU & UK References

Vulnerability details

Deserialization of Untrusted Data vulnerability in ThemeREX Classter classter allows Object Injection.This issue affects Classter: from n/a through <= 2.5.

CWE(s)
CWE-502

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

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.
attack.mitre.org →
Why these techniques?

Direct RCE via unauthenticated deserialization in public-facing WordPress theme maps cleanly to T1190.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2025-62368Shared CWE-502
CVE-2025-68903Shared CWE-502
CVE-2025-67911Shared CWE-502
CVE-2025-54014Shared CWE-502
CVE-2026-22505Shared CWE-502
CVE-2025-53078Shared CWE-502
CVE-2026-43633Shared CWE-502
CVE-2025-60039Shared CWE-502
CVE-2026-25429Shared CWE-502
CVE-2025-7697Shared CWE-502

Affected Assets

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SI-2 Flaw Remediation good match
prevent

Directly addresses the CVE by requiring identification, reporting, and correction of the deserialization flaw in Classter versions through <=2.5.

SI-10 Information Input Validation good match
prevent

Mandates validation of untrusted inputs to block malicious serialized data from triggering PHP object injection.

RA-5 Vulnerability Monitoring and Scanning partial match
preventdetect

Scans for and remediates vulnerabilities like CVE-2025-54001 in the Classter WordPress theme.

References