CVE-2025-53990: 
WordPress vulnerability analysis and mitigation

CVE-2025-53990 is a PHP Object Injection vulnerability (Deserialization of Untrusted Data) in the JetFormBuilder WordPress plugin by Crocoblock (jetmonsters). It affects all versions up to and including 3.5.1.2, and was reported on June 23, 2025, with public disclosure on July 16, 2025. The vulnerability carries a CVSS v3.1 base score of 7.2 (High), requiring Administrator-level privileges to exploit (Patchstack, Red Hat CVE).

The vulnerability is classified as CWE-502 (Deserialization of Untrusted Data), mapped to CAPEC-586 (Object Injection). An authenticated attacker with Administrator-level privileges can supply crafted serialized PHP data that the plugin deserializes without adequate validation, enabling PHP Object Injection. If a suitable Property-Oriented Programming (POP) chain exists within the WordPress environment, this can be leveraged to achieve code injection, SQL injection, path traversal, or denial of service (Patchstack).

Successful exploitation could allow an attacker with administrator access to perform code injection, SQL injection, path traversal, or denial of service, depending on the availability of a suitable POP chain in the target environment. This could result in full compromise of the WordPress site, including unauthorized access to sensitive data, modification of site content, and potential lateral movement to the underlying server (Patchstack).

The EPSS score for CVE-2025-53990 is approximately 0.035% (very low), and there is no evidence of active in-the-wild exploitation or inclusion in the CISA KEV catalog at this time. Exploitation requires Administrator-level privileges, which significantly limits the attack surface. Patchstack classifies this as low priority with no impactful threat currently identified, though they note that similar vulnerabilities are sometimes used in mass-exploit campaigns (Patchstack, Feedly).

1. Reconnaissance: Identify WordPress sites running JetFormBuilder plugin version 3.5.1.2 or earlier using tools like WPScan or Shodan.
2. Obtain Administrator Access: Gain administrator credentials through phishing, credential stuffing, or other means, as the vulnerability requires Administrator-level privileges.
3. Identify Injection Point: Locate the plugin functionality that processes serialized PHP data without proper validation.
4. Craft Malicious Payload: Construct a serialized PHP object payload that exploits an available POP chain within the WordPress installation (e.g., leveraging classes from installed themes or plugins).
5. Submit Payload: Submit the crafted serialized data through the vulnerable JetFormBuilder input, triggering deserialization on the server.
6. Achieve Objective: Depending on the POP chain available, achieve code execution, SQL injection, file read/write, or denial of service on the target server (Patchstack).

• Logs: WordPress access logs showing unusual POST requests to JetFormBuilder endpoints containing serialized PHP data (e.g., O: patterns in request bodies); PHP error logs indicating deserialization errors or unexpected object instantiation.
• File System: Unexpected new PHP files or web shells in the WordPress uploads or plugin directories; modifications to existing plugin files.
• Process: Unusual child processes spawned by the web server process (e.g., bash, curl, wget) following form submission activity.
• Database: Unexpected changes to WordPress database tables, particularly wp_options or user tables, following administrator-level activity.

Update JetFormBuilder to version 3.5.2 or later, which contains the fix for this vulnerability. No configuration-based workaround is available; upgrading is the only recommended remediation. Patchstack users can enable auto-update for vulnerable plugins to receive protection automatically (Patchstack).

The vulnerability was covered in Wordfence's weekly WordPress vulnerability report for July 14–20, 2025, and included in Sucuri's WordPress vulnerability patch roundup for July 2025, indicating routine industry tracking without significant alarm given the high privilege requirement (Wordfence Blog, Sucuri Blog).