CVE-2025-3439

Everest Forms – Contact Form, Quiz, Survey, Newsletter & Payment Form Builder for WordPress <= 3.1.1 - Unauthenticated PHP Object Injection

2025-04-10 00:00
kuaile

Strategic Overview

Status
Patched in 3.1.2
Affected Plugin
Everest Forms – Contact Form, Payment Form, Quiz, Survey & Custom Form Builder with AI
Affected Version
<= 3.1.1
CVSS
9.8Critical
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2025-3439
View all Everest Forms – Contact Form, Payment Form, Quiz, Survey & Custom Form Builder with AI vulnerabilities

At a glance

CVE-2025-3439 is a critical-severity Deserialization of Untrusted Data vulnerability in the Everest Forms WordPress plugin, affecting versions <= 3.1.1. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 3.1.2; sites on affected versions should update now. Disclosed April 2025, reported by kuaile.

Vulnerability Overview

The Everest Forms – Contact Form, Quiz, Survey, Newsletter & Payment Form Builder for WordPress plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 3.1.1 via deserialization of untrusted input from the 'field_value' parameter. This makes it possible for unauthenticated attackers to inject a PHP Object. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-502: Deserialization of Untrusted Data

Everest Forms <= 3.1.1 carries this weakness at field_value, and reaching it takes no account at all. Deserialization of untrusted data means the application reconstructs objects from input a caller controls, letting the attacker choose which classes get instantiated and what their properties hold.

A workable chain turns deserialization into file writes, deletions or code execution, depending on what the loaded classes do in their magic methods. For Everest Forms the fix is 3.1.2: builds <= 3.1.1 are affected, anything from 3.1.2 onward is not.

Remediation

Update to version 3.1.2, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Everest Forms 3.1.2 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Login Security

External References

https://www.cve.org/CVERecord?id=CVE-2025-3439https://www.wordfence.com/threat-intel/vulnerabilities/id/0e5617a2-5670-4d98-a36b-942f71634642https://nvd.nist.gov/vuln/detail/CVE-2025-3439

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C