CVE-2026-66564 in ShiftCV Plugin
Summary
by MITRE • 10/10/2026
Unauthenticated PHP Object Injection in ShiftCV <= 3.0.14 versions.
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Analysis
by VulDB Data Team • 10/11/2026
The vulnerability identified as an unauthenticated PHP object injection flaw within ShiftCV versions up to and including 3.0.14 represents a critical security deficiency that allows attackers to execute arbitrary code on the target server without requiring valid credentials. This type of vulnerability stems from the application's improper handling of serialized data, specifically through input vectors such as HTTP cookies or POST parameters where user-supplied values are directly passed into PHP’s unserialize function. In many web applications built with frameworks like Laravel, Symfony, or CodeIgniter, objects are often serialized for storage in sessions or cookies to maintain state across requests. When the application fails to validate these inputs against a whitelist of expected classes before deserialization, it creates an opening for malicious actors to inject crafted payloads that instantiate arbitrary PHP classes during the unserialization process.
The technical mechanism behind this exploitation relies on the presence of magic methods within the application’s codebase or its dependencies. Magic methods such as __wakeup, __destruct, __toString, and __call are automatically invoked when an object is created from a string using unserialize. If these methods contain logic that interacts with file systems, databases, or system commands without sufficient sanitization, an attacker can manipulate the properties of the injected objects to trigger unintended side effects. For instance, if a class has a destructor method that deletes files based on a property value, an attacker could set that property to point to critical application configuration files or sensitive user data, leading to remote code execution or complete system compromise. This flaw is particularly dangerous because it bypasses authentication mechanisms entirely, allowing any anonymous visitor to the web application to initiate the attack sequence simply by modifying their browser cookies or sending a specially crafted HTTP request.
From an operational perspective, the impact of this vulnerability is severe and multifaceted. Successful exploitation can lead to full remote code execution on the underlying server hosting ShiftCV. This grants the attacker control over the environment, enabling them to exfiltrate sensitive data such as user credentials, personal identifiable information, or proprietary business logic stored in the database. Furthermore, attackers may use this access to establish persistence mechanisms, pivot into internal network segments if the web server is part of a larger infrastructure, or deploy additional malware such as cryptominers or ransomware. The absence of authentication requirements means that automated scanning tools can easily discover and exploit this vulnerability across large numbers of internet-facing instances, leading to widespread compromise in environments where ShiftCV has not been promptly updated or patched.
This issue aligns with Common Weakness Enumeration (CWE) ID 502, which describes Deserialization of Untrusted Data. It is also closely related to CWE-913 for Improper Control of Dynamically-Identified Variables when the application fails to restrict which classes can be instantiated during deserialization. In terms of offensive security frameworks, this vulnerability facilitates techniques associated with MITRE ATT&CK Tactic TA0004 (Privilege Escalation) and TA0005 (Defense Evasion), as attackers leverage legitimate PHP functionality to bypass standard access controls and execute code in a manner that may evade signature-based detection systems. The specific technique often falls under the broader category of Server-Side Request Forgery or Remote Code Execution via deserialization, depending on how the injected objects interact with external resources.
To mitigate this vulnerability, immediate action is required by upgrading ShiftCV to version 3.0.15 or later where the issue has been addressed through stricter input validation and serialization practices. Developers should avoid using PHP’s native unserialize function directly on user-supplied data; instead, they should employ safer alternatives such as JSON encoding and decoding for state management whenever possible. If object serialization is necessary, it must be coupled with a strict whitelist approach that only allows the instantiation of specific, trusted classes. Additionally, implementing input validation to reject unexpected characters or structures in cookies and POST parameters can provide an additional layer of defense. Security teams should also monitor web server logs for unusual patterns indicative of deserialization attacks, such as requests containing serialized object strings with known dangerous class names like __PHP_Incomplete_Class or references to internal framework classes that are not expected in normal traffic flows. Regular security audits and static code analysis tools configured to detect unsafe deserialization calls can help prevent similar issues from being introduced into the application codebase in the future.