Overview
In today’s blog post, we delve into an important cybersecurity vulnerability, CVE-2025-39410, that has been discovered in the widely used Smart Sections Theme Builder – WPBakery Page Builder Addon. This vulnerability pertains to deserialization of untrusted data, a common area of vulnerability in web applications that could potentially lead to system compromise or data leakage. It is crucial to understand this vulnerability due to the widespread use of the affected product across a diverse range of websites.
Vulnerability Summary
CVE ID: CVE-2025-39410
Severity: Critical (9.8/10)
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: System Compromise or Data Leakage
Affected Products
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Product | Affected Versions
Smart Sections Theme Builder – WPBakery Page Builder Addon | n/a through 1.7.8
How the Exploit Works
The exploit takes advantage of the Deserialization of Untrusted Data vulnerability. In essence, deserialization is the process where data is converted from a format suitable for storage or transmission back to an object. The vulnerability arises when an application deserializes data without properly validating or sanitizing it. An attacker can manipulate the serialized data to modify the application’s logic, execute arbitrary code, or instigate other malicious activities.
Conceptual Example Code
The following is a conceptual example of how the vulnerability might be exploited. Please note that this is a simplified representation and actual payloads would be more complex.
POST /themeBuilder/modify HTTP/1.1
Host: target.example.com
Content-Type: application/json
{ "themeData": "[malicious serialized object]" }In this example, the attacker sends a POST request with a malicious serialized object in the `themeData` field. If the server deserializes this object without proper validation, the attacker could gain unauthorized control over the system or cause data leakage.
Recommendations for Mitigation
Users of the Smart Sections Theme Builder – WPBakery Page Builder Addon are recommended to immediately apply the patch provided by the vendor. If the patch cannot be applied immediately, users can implement a Web Application Firewall (WAF) or Intrusion Detection System (IDS) as a temporary mitigation method to guard against potential exploitation of this vulnerability. It is crucial to update the affected product to a patched version as soon as feasible to ensure optimal security.