CVE-2026-65575 in Accalia Plugin
Summary
by MITRE • 08/06/2026
Unauthenticated PHP Object Injection in Accalia <= 1.5.3 versions.
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Analysis
by VulDB Data Team • 08/06/2026
This vulnerability represents a critical security flaw in the Accalia content management system affecting versions 1.5.3 and earlier, where an unauthenticated attacker can inject arbitrary PHP objects through improper input validation mechanisms. The vulnerability stems from insufficient sanitization of user-supplied data that is subsequently serialized and deserialized within the application's processing pipeline. According to CWE-502, this falls under the category of Deserialization of Untrusted Data, which allows attackers to execute malicious code by manipulating serialized object structures passed to the unserialize() function. The flaw exists in the application's handling of parameters that are directly fed into PHP's deserialization process without adequate validation or sanitization measures.
The technical exploitation occurs when an attacker crafts malicious serialized data that, upon being processed by the vulnerable application, triggers unintended object instantiation and method execution within the PHP environment. This creates a pathway for remote code execution capabilities as demonstrated in similar vulnerabilities found across various CMS platforms and web applications. The impact extends beyond simple data manipulation to potentially allow full system compromise through arbitrary code execution. Attackers can leverage this vulnerability to execute commands on the server, escalate privileges, or establish persistent backdoors within the target environment.
The operational implications of this vulnerability are severe for organizations using affected Accalia versions, as it eliminates the need for authentication to exploit the flaw. This makes the attack surface significantly broader since any user with access to the web application can potentially exploit the vulnerability regardless of their authorization status. The vulnerability's presence in the core deserialization logic means that successful exploitation could lead to complete system compromise and data exfiltration. Organizations using Accalia versions prior to 1.5.4 should immediately implement mitigations as the attack vector requires no privileged access or specialized knowledge beyond basic web application exploitation techniques.
Mitigation strategies should include immediate patching of the affected software to version 1.5.4 or later, which addresses the deserialization vulnerability through proper input validation and sanitization. Additionally, implementing proper parameter validation at all entry points where user input is processed, particularly those involving serialization functions, provides defense in depth. Network-level protections such as web application firewalls can help detect and block malicious payloads attempting to exploit this vulnerability. According to ATT&CK framework technique T1203, this type of vulnerability falls under the category of Exploitation for Client Execution, where attackers leverage application flaws to execute arbitrary code on target systems. Organizations should also consider implementing runtime protections that monitor deserialization activities and flag suspicious object instantiation patterns to prevent successful exploitation attempts.
The vulnerability highlights the critical importance of secure coding practices in preventing object injection attacks, particularly when dealing with serialization functions in PHP applications. Proper input validation combined with secure deserialization practices forms a fundamental defense against such vulnerabilities, as recommended by OWASP Top Ten security controls for preventing deserialization attacks. Regular security assessments and code reviews focusing on serialization handling can help identify similar vulnerabilities across the application codebase. The presence of this flaw in the Accalia platform demonstrates how seemingly simple input handling mechanisms can create significant security risks when proper validation procedures are not implemented, emphasizing the need for comprehensive security testing throughout the software development lifecycle to prevent such critical flaws from reaching production environments.