Description

Deserialization of Untrusted Data vulnerability in Axiomthemes Veto veto allows Object Injection.This issue affects Veto: from n/a through 1.6.0.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-10-10T08:17:05.050Z",
  "pubdate": "2026-10-10T08:17:05.050Z",
  "executiveSummary": "The Axiomthemes Veto theme is susceptible to an Object Injection vulnerability resulting from the insecure deserialization of untrusted data. This flaw permits an unauthenticated or low-privileged attacker to inject malicious serialized objects into the application, which are subsequently processed by the system's deserialization logic.\nBy manipulating the serialized input, an attacker can influence the state of existing application objects or trigger unintended code execution paths within the underlying PHP environment. Successful exploitation allows for a broad range of malicious activities, including unauthorized file system access, remote code execution (RCE), or the potential for complete system compromise, depending on the available gadget chains within the theme's codebase or installed plugins.\nThe vulnerability affects all versions of the Veto theme from n/a through 1.6.0. Given the nature of insecure deserialization, the impact is severe, potentially leading to a total loss of confidentiality, integrity, and availability of the affected WordPress site. There are no specific complex prerequisites mentioned for exploitation other than the ability to supply crafted input to a vulnerable endpoint that deserializes data without prior validation or cryptographic verification.",
  "technicalDetails": "The root cause of this vulnerability lies in the application's reliance on native PHP serialization mechanisms, specifically the use of 'unserialize()' on user-controlled input without adequate sanitization or an allow-list verification process. Insecure deserialization occurs when the application accepts a serialized string and restores it into a PHP object structure without first validating the data integrity or the type of object being instantiated.\nThe attack flow begins when an attacker identifies an endpoint or hidden parameter within the Veto theme that accepts serialized data as part of an HTTP request. The attacker crafts a malicious payload representing a serialized object designed to leverage 'POP chains' (Property Oriented Programming). These chains consist of existing code fragments ('gadgets') already present within the application's scope—such as class methods like '__destruct', '__wakeup', or '__toString'—that can be repurposed when their properties are restored during the deserialization process.\nOnce the attacker submits the crafted payload, the application invokes the deserialization function. If the object being instantiated contains magic methods that perform dangerous operations—such as file manipulation, database queries, or command execution—the attacker can trigger these actions with high-privilege context. The payload behavior is entirely dependent on the available gadget chains; an attacker can chain multiple gadgets together to bypass traditional security filters and achieve arbitrary code execution.\nThe vulnerable component is the theme's core logic that handles input processing where data serialization is implemented. Because this affects the Veto theme (versions n/a through 1.6.0), any environment running these versions is inherently insecure if it relies on these deserialization functions. The exploitation does not require advanced network-level access, provided the vulnerable endpoint is reachable via standard web protocols. Post-exploitation impact can include unauthorized modification of site content, exfiltration of sensitive configuration files (e.g., wp-config.php), or the installation of persistent backdoors, thereby granting the attacker long-term control over the compromised infrastructure."
}