A critical security vulnerability has been identified in the Sabuj Kundu CBX Poll WordPress plugin, tracked as CVE-2025-31612. This flaw, involving deserialization of untrusted data, could allow attackers to execute arbitrary code on affected systems. The vulnerability affects all versions up to and including 1.2.7 of the plugin and carries a CVSS v3.1 score of 9.8, indicating its critical nature.
Vulnerability Overview
The CBX Poll plugin vulnerability stems from improper handling of serialized data in PHP. Attackers can exploit this weakness by sending specially crafted payloads that, when deserialized, create arbitrary objects in the application’s memory space. This object injection could lead to remote code execution under the web server’s privileges. The vulnerability was discovered during a routine security audit by Patchstack researchers and publicly disclosed on April 1, 2025.
According to the CVE details, the flaw requires no authentication, making it particularly dangerous for websites running vulnerable versions of the plugin. The attack vector is network-based, and successful exploitation could compromise the entire WordPress installation. The vulnerability has been assigned CWE-502 (Deserialization of Untrusted Data) in the Common Weakness Enumeration database.
Technical Analysis
The vulnerability occurs when the plugin processes user-supplied data without proper validation before deserialization. PHP’s unserialize() function, when called on malicious input, can instantiate objects of arbitrary classes present in the application’s scope. Attackers can leverage this behavior to execute methods or access properties that lead to code execution.
The CVSS v3.1 vector string (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) reveals several critical aspects of this vulnerability. It is network exploitable (AV:N), requires low attack complexity (AC:L), needs no privileges (PR:N), and has no user interaction requirements (UI:N). The impact metrics show complete compromise of confidentiality, integrity, and availability (C:H/I:H/A:H) with scope unchanged (S:U).
| Component | Details |
|---|---|
| Affected Versions | CBX Poll n/a through 1.2.7 |
| Vulnerability Type | Object Injection via Deserialization |
| CVSS Score | 9.8 (Critical) |
| Attack Vector | Network |
| Privileges Required | None |
Mitigation and Remediation
As of the publication date, there is no official patch available for this vulnerability. The recommended course of action is to immediately disable or remove the CBX Poll plugin from all WordPress installations. Website administrators should monitor the official plugin repository for updates and apply them as soon as they become available.
For environments where the plugin functionality is essential, temporary mitigation measures include implementing web application firewall rules to block suspicious serialized data patterns. PHP configurations can be hardened by restricting allowed classes during deserialization using the allowed_classes option in unserialize(). However, these measures should not be considered permanent solutions.
Detection and Monitoring
Organizations should scan their WordPress installations for the presence of the CBX Poll plugin and identify any instances running vulnerable versions. Log monitoring should be enhanced to detect unusual activity patterns that might indicate exploitation attempts, particularly focusing on requests containing serialized PHP data structures.
Security teams should watch for emerging proof-of-concept exploits, though none have been publicly released at the time of writing. The EPSS (Exploit Prediction Scoring System) score for this vulnerability is pending, but given the critical CVSS rating, the likelihood of exploit development is high.
Conclusion
CVE-2025-31612 represents a serious threat to WordPress sites using the CBX Poll plugin. The combination of high impact and ease of exploitation makes this vulnerability particularly dangerous. Organizations should prioritize identifying and mitigating affected systems while awaiting an official patch from the plugin developer.
The discovery of this vulnerability highlights the ongoing risks associated with third-party WordPress plugins and the importance of maintaining an up-to-date inventory of all installed components. Regular security audits and timely patching remain essential practices for maintaining web application security.
References
- “CVE-2025-31612 – Sabuj Kundu CBX Poll Object Injection Vulnerability,” cvefeed.io, 2025.
- “WordPress CBX Poll Plugin 1.2.7 PHP Object Injection Vulnerability,” Patchstack, 2025.
- “CWE-502: Deserialization of Untrusted Data,” MITRE, 2025.
