Simple Event Planner Object Injection Vulnerability

Executive Summary

CVE-2026-97257 is a PHP Object Injection vulnerability in the WordPress Simple Event Planner Plugin versions 1.5.7 and earlier. It allows attackers with contributor or developer-level access to manipulate data processing and execute harmful server actions through deserialization of untrusted data.

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Detection Guidance

To detect this vulnerability, check if you are running Simple Event Planner versions 1.5.7 or earlier. Inspect server logs for unusual activity or signs of object injection attempts. Use security plugins or tools that monitor for deserialization flaws in WordPress environments.

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Impact Analysis

This vulnerability can lead to unauthorized server actions, potential data breaches, or complete system compromise. Attackers could exploit it in mass campaigns targeting thousands of websites, making it a significant risk for WordPress sites using the vulnerable plugin version.

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Compliance Impact

This vulnerability could lead to unauthorized data access or manipulation, potentially violating GDPR's data integrity and confidentiality requirements. For HIPAA, it may expose protected health information if exploited in healthcare-related WordPress plugins.

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Mitigation Strategies

Immediately update Simple Event Planner to version 1.5.8 or later. If updating is not possible, apply Patchstack's mitigation rule to block attacks until the update is applied. Remove unnecessary user roles with contributor or developer privileges to reduce exploitation risk.

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