CVE-2026-13167

Everest Forms – Contact Form, Payment Form, Quiz, Survey & Custom Form Builder with AI <= 3.5.2 - Missing Authorization to Authenticated (Delegated+) Arbitrary Plugin Activation via REST API and AJAX Endpoints

2026-08-15 00:00
skyv3il

Strategic Overview

At a glance

CVE-2026-13167 is a medium-severity Missing Authorization vulnerability in the Everest Forms WordPress plugin, affecting versions <= 3.5.2. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Delegated level or above. The issue is fixed in version 3.5.3; sites on affected versions should update now. Disclosed August 2026, reported by skyv3il.

Vulnerability Overview

The Everest Forms – Contact Form, Payment Form, Quiz, Survey & Custom Form Builder with AI plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 3.5.2. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for authenticated attackers, with delegated form management access and above, to activate arbitrary already-installed WordPress plugins — including previously deactivated or vulnerable plugins — without holding the core activate_plugins capability. Exploitation requires the target user to hold a delegated Everest Forms capability (manage_everest_forms, everest_forms_create_forms, or everest_forms_view_forms), which the plugin's own roles and permissions tool allows administrators to assign to non-administrator roles such as Author; the nonces required to exploit the AJAX handlers are emitted on EVF admin pages accessible to any such delegated user.

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 interaction from a victim user.

CWE-862: Missing Authorization

Reaching this weakness in Everest Forms <= 3.5.2 takes an account at Delegated level or above. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.

Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For Everest Forms the fix is 3.5.3: builds <= 3.5.2 are affected, anything from 3.5.3 onward is not.

Remediation

Update to version 3.5.3, or a newer patched version

How does WordSec protect against this?

Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: Everest Forms 3.5.3 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

Related records

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