CVE-2026-118562 in Single Content Sync Plugin
Summary
by MITRE • 10/30/2026
Deserialization of Untrusted Data vulnerability in Drupal Single Content Sync allows Object Injection. This issue affects Single Content Sync versions: from 0.0.0 to 1.4.19.
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Analysis
by VulDB Data Team • 10/30/2026
The vulnerability identified within the Drupal module Single Content Sync represents a critical security flaw rooted in the insecure deserialization of untrusted data, which directly facilitates Object Injection attacks. This issue affects all versions of the module ranging from version 0.0.0 up to and including version 1.4.19. The core technical failure lies in the application's handling of serialized PHP objects received during synchronization processes without adequate validation or sanitization. When an attacker provides maliciously crafted input, they can manipulate the deserialization process to instantiate arbitrary classes with controlled properties, thereby gaining the ability to execute code within the context of the web server user account. This type of vulnerability is classified under CWE-502, which denotes Deserialization of Untrusted Data, and it aligns with MITRE ATT&CK technique T1190, Exploit Public-Facing Application, as well as T1059, Command and Scripting Interpreter, due to the potential for remote code execution.
The operational impact of this vulnerability is severe, allowing authenticated attackers or potentially unauthenticated ones depending on module configuration and exposed endpoints to achieve full system compromise. By exploiting the object injection flaw, an attacker can bypass standard access controls and execute arbitrary PHP commands on the underlying server infrastructure. This capability enables the exfiltration of sensitive data stored within the Drupal database, including user credentials, personal information, and proprietary content. Furthermore, it allows for the installation of persistent backdoors or web shells that facilitate ongoing unauthorized access even after initial patches are applied to other parts of the system. The lack of strict type checking during deserialization means that any serialized string containing a class name can trigger unintended side effects if those classes have methods with dangerous functionality such as file operations, database queries, or network connections.
Mitigation strategies must prioritize immediate remediation through software updates and architectural changes to prevent future occurrences. Administrators running affected versions of Single Content Sync should upgrade immediately to version 1.4.20 or later where the vulnerability has been addressed by implementing strict input validation and whitelisting allowed classes for deserialization. In cases where upgrading is not immediately feasible, temporary mitigations include disabling the specific synchronization endpoints that process untrusted serialized data if they are not essential for current operations. Additionally, enforcing Content Security Policy headers can help mitigate some downstream effects of code execution, although this does not address the root cause. Long-term security posture improvements should involve adopting secure coding practices such as using JSON instead of PHP serialize for data interchange whenever possible, implementing rigorous input validation frameworks, and conducting regular third-party penetration testing to identify similar deserialization flaws across other modules in the Drupal ecosystem.