Executive Summary

CVE-2026-39557 is a high-priority PHP Object Injection vulnerability found in the WordPress NeoBeat Theme versions 1.7 and below.

This vulnerability allows unauthenticated attackers to inject malicious PHP objects, potentially leading to code execution, SQL injection, path traversal, denial of service, and other harmful actions if a suitable POP (Property Oriented Programming) chain exists.

It is classified under the OWASP Top 10 category A3: Injection and has a CVSS score of 8.1, indicating a high severity.

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Impact Analysis

This vulnerability can have severe impacts including unauthorized code execution, which could allow attackers to take control of the affected website.

It can also lead to SQL injection, enabling attackers to manipulate or steal data from the database.

Other possible impacts include path traversal attacks, denial of service conditions, and other malicious activities that could disrupt website operations or compromise data integrity.

Because the exploit requires no authentication, it can be used by attackers remotely without any prior access.

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Detection Guidance

The vulnerability affects WordPress sites using the NeoBeat theme version 1.7 or below and is exploitable without authentication. Detection can focus on identifying the presence of the vulnerable theme version on your system.

A practical approach is to check the installed theme version via WordPress admin or by inspecting the theme files directly.

• Use WP-CLI to check the theme version: wp theme list --status=active
• Manually inspect the style.css file in the NeoBeat theme directory for the version number.

Network detection can involve monitoring for suspicious HTTP requests attempting PHP Object Injection payloads targeting the NeoBeat theme endpoints, but specific commands or signatures are not provided.

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Mitigation Strategies

The primary mitigation step is to update the NeoBeat theme to version 1.8 or later, which contains the patch for this vulnerability.

Until the update can be applied, users are advised to implement mitigation measures such as applying Patchstack's mitigation rule to block attacks targeting this vulnerability.

Because the vulnerability is unauthenticated and can be exploited remotely, immediate patching or blocking exploit attempts is critical to prevent code injection, SQL injection, path traversal, denial of service, and other attacks.

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Compliance Impact

The vulnerability in NeoBeat versions 1.7 and below allows unauthenticated PHP Object Injection, which can lead to code execution, SQL injection, path traversal, and denial of service attacks. Such security weaknesses can result in unauthorized access to sensitive data or disruption of services.

Because of these risks, organizations using the affected NeoBeat versions may face challenges in maintaining compliance with standards and regulations like GDPR and HIPAA, which require protection of personal and sensitive data against unauthorized access and breaches.

Failure to patch or mitigate this vulnerability could lead to data breaches or service interruptions, potentially resulting in non-compliance with these regulations and associated legal or financial consequences.

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