CVE-2026-112856 in Vagabonds Plugin
Summary
by MITRE • 10/23/2026
Deserialization of Untrusted Data vulnerability in ThemeREX Group Vagabonds vagabonds allows Object Injection.This issue affects Vagabonds: from n/a through 1.3.10.
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Analysis
by VulDB Data Team • 10/23/2026
The identified security flaw represents a critical deserialization vulnerability within the Vagabonds theme developed by ThemeREX Group, specifically affecting versions ranging from initial releases up to version 1.3.10. This type of vulnerability falls under the category of insecure deserialization, which is consistently ranked as one of the most dangerous web application security risks according to industry standards such as CWE-502 and OWASP Top 10 guidelines. The core issue stems from the application's failure to properly validate or sanitize data before processing it through a serialization mechanism that allows for object instantiation. When an attacker supplies maliciously crafted serialized objects, the underlying PHP engine interprets these inputs not merely as static data but as executable code structures, leading directly to remote object injection.
From a technical perspective, this vulnerability exploits the way certain frameworks handle untrusted input during the deserialization process. In environments where user-supplied data is converted back into native objects without rigorous type checking or integrity verification, an attacker can manipulate internal properties of these objects. By crafting specific payloads that target known gadget chains within the PHP runtime environment or associated libraries used by the theme, the attacker gains the ability to execute arbitrary functions. This bypasses standard authentication and authorization controls because the exploitation occurs at a lower level where access checks are often not enforced during object reconstruction. The impact is severe, as it effectively grants an unauthenticated remote code execution capability if the vulnerable function does not require prior login credentials, or elevates privileges for authenticated users to achieve full system compromise depending on the web server's user context.
The operational impact of this vulnerability extends beyond simple data leakage. An attacker leveraging this object injection flaw can read sensitive files from the server filesystem, such as configuration files containing database credentials or API keys. Furthermore, they can write malicious scripts into accessible directories, potentially establishing a persistent backdoor for future access. In more advanced scenarios involving specific gadget chains, the vulnerability allows for complete remote code execution, enabling the attacker to run system commands with the privileges of the web server process. This level of control facilitates lateral movement within the network, data exfiltration on an industrial scale, and potential disruption of service through resource exhaustion or destructive file manipulation. The presence of this flaw indicates a significant gap in input validation practices during the development lifecycle of the theme.
To mitigate this risk, immediate action is required to update the Vagabonds theme to version 1.3.11 or any later release where the vendor has implemented proper fixes for deserialization issues. Until an update is applied, administrators should consider restricting file uploads and disabling potentially dangerous PHP functions if possible within their server configuration. It is also advisable to implement strict input validation on all endpoints that process user data, ensuring that only expected data types are accepted. For long-term security posture improvement, development teams should adopt secure coding practices that avoid using native deserialization methods with untrusted input entirely. Instead, they should utilize safer alternatives such as JSON for data interchange or employ whitelisting mechanisms to validate object classes before instantiation. Regular vulnerability scanning and code reviews focusing on serialization logic are essential to prevent similar flaws in future iterations of the software.