Cyber Resilience

CVE-2026-27437

CriticalRCE

Published: 05 March 2026

Published
05 March 2026
Modified
22 April 2026
KEV Added
—
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 0.0037 29.2th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-27437 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 29.2th 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-2026-27437 is a Deserialization of Untrusted Data vulnerability (CWE-502) in the ThemeREX Tennis Club WordPress theme, also known as tennis-sportclub, that allows Object Injection. This issue affects all versions of the theme from n/a through 1.2.3.

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 critical severity. An unauthenticated attacker can exploit it remotely over the network with low attack complexity and no user interaction required, potentially achieving high impacts on confidentiality, integrity, and availability via injected objects.

The Patchstack advisory at https://patchstack.com/database/Wordpress/Theme/tennis-sportclub/vulnerability/wordpress-tennis-club-theme-1-2-3-php-object-injection-vulnerability?_s_id=cve documents this PHP Object Injection vulnerability in the Tennis Club theme version 1.2.3.

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 Tennis Club tennis-sportclub allows Object Injection.This issue affects Tennis Club: from n/a through <= 1.2.3.

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?

Remote unauthenticated PHP object injection (deserialization) in a public-facing WordPress theme directly enables exploitation of a public-facing application for initial access and high-impact effects.

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

CVEs Like This One

CVE-2025-62368Shared CWE-502
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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

Flaw remediation directly mitigates CVE-2026-27437 by applying patches or updates to the vulnerable ThemeREX Tennis Club WordPress theme, preventing object injection exploitation.

SI-10 Information Input Validation good match
prevent

Information input validation comprehensively addresses deserialization of untrusted data by validating serialized inputs before processing in the vulnerable theme.

SI-9 Information Input Restrictions partial match
prevent

Information input restrictions limit the types, formats, or sizes of inputs that could contain malicious serialized objects targeting the deserialization vulnerability.

References