A critical deserialization vulnerability in the Integration for ActiveCampaign plugin allows unauthenticated attackers to execute arbitrary code on the host system.

The vulnerability is rooted in the insecure deserialization of untrusted data. An unauthenticated attacker can exploit this by sending a crafted payload to the affected plugin, bypassing security controls to execute malicious code.

With a CVSS score of 9.8, this vulnerability is critical. Successful exploitation allows an attacker to gain unauthorized control over the web server, which could lead to sensitive data exfiltration, modification of site content, or the installation of persistent backdoors.

Immediate Action: Upgrade the affected plugin to the latest version immediately to patch the insecure deserialization logic.

Proactive Monitoring: Review application and server access logs for anomalous traffic or unexpected execution patterns that deviate from normal plugin behavior.

Compensating Controls: Utilize a Web Application Firewall (WAF) to filter out common PHP object injection patterns and block malicious HTTP requests.

Public Exploit Available: false

This vulnerability presents a high risk of remote code execution. Organizations utilizing these integration plugins must prioritize patching, as unauthenticated RCE vulnerabilities are frequently targeted by automated exploit campaigns.