CVE-2026-65577 in Advice Plugin
Summary
by MITRE • 08/06/2026
Unauthenticated PHP Object Injection in Advice <= 1.18.0 versions.
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Analysis
by VulDB Data Team • 08/06/2026
This vulnerability represents a critical security flaw in the Advice plugin for WordPress systems where unauthenticated remote code execution can occur through PHP object injection attacks. The issue stems from improper input validation and sanitization of user-supplied data within the plugin's core functionality, allowing attackers to manipulate serialized PHP objects without requiring authentication credentials. The vulnerability specifically affects versions 1.18.0 and earlier, making it a widespread concern for WordPress administrators who have not updated their installations. According to CWE-502, this falls under the category of deserialization of untrusted data, where maliciously crafted serialized objects can be executed within the PHP environment. The attack vector typically involves manipulating parameters that are processed through PHP's unserialize() function, which can lead to arbitrary code execution on the target server.
The technical implementation of this vulnerability exploits the inherent dangers of PHP's serialization mechanism, where attackers can craft malicious serialized object payloads that, when processed by the vulnerable Advice plugin, trigger unintended behavior within the application. The flaw occurs because the plugin fails to properly validate or sanitize data before passing it to PHP's unserialize() function, creating a pathway for attackers to inject malicious objects that execute code on the target system. This type of vulnerability aligns with ATT&CK technique T1059.007 for command and script injection, where adversaries leverage application weaknesses to execute arbitrary commands. The impact extends beyond simple code execution, potentially allowing attackers to gain full control over the affected WordPress installation, compromise user data, or use the compromised system as a launching point for further attacks within the network infrastructure.
The operational consequences of this vulnerability are severe and far-reaching for organizations using affected versions of the Advice plugin. Attackers can leverage this weakness to establish persistent backdoors, exfiltrate sensitive data, modify website content, or even deploy additional malware payloads. The unauthenticated nature of the exploit means that any visitor to the compromised website could potentially trigger the vulnerability, making it particularly dangerous for high-traffic sites. Organizations may face regulatory compliance issues if user data is compromised, and the reputational damage from a successful attack can be substantial. Additionally, the vulnerability creates opportunities for attackers to use the compromised system for botnet activities, spam distribution, or as part of larger distributed attacks against other targets. The exploitation process typically requires minimal privileges and can be automated, making it attractive to both skilled and less sophisticated threat actors.
Mitigation strategies should focus on immediate remediation through plugin updates to versions that address the PHP object injection vulnerability, as well as implementing additional security measures such as input validation, web application firewalls, and monitoring for suspicious activity. Organizations should conduct thorough security assessments of their WordPress installations to identify all vulnerable plugins and ensure proper patch management procedures are in place. The implementation of security headers, proper access controls, and regular security audits can help reduce the attack surface and prevent exploitation attempts. Furthermore, maintaining up-to-date security tools and implementing intrusion detection systems can provide early warning capabilities when potential exploitation attempts occur. Regular security training for administrators and developers regarding secure coding practices, particularly around serialization and data handling, remains essential for preventing similar vulnerabilities in future development efforts.