CVE-2026-110721

NotificationX <= 3.3.3 - Missing Authorization to Unauthenticated Arbitrary Content Injection via 'nx_id' Parameter on /popup-submit REST Route

2026-10-15 16:22
Eunho Kim

At a glance

CVE-2026-110721 is a medium-severity Missing Authorization vulnerability in the NotificationX WordPress plugin, affecting versions <= 3.3.3. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 3.3.4; sites on affected versions should update now. Disclosed October 2026, reported by Eunho Kim.

Vulnerability Overview

The NotificationX plugin for WordPress is vulnerable to Missing Authorization leading to arbitrary content injection in versions up to, and including, 3.3.3 The /notificationx/v1/popup-submit REST route is registered with permission_callback => '__return_true', and the handler at PopupNotification::handle_popup_submission() accepts an attacker-controlled nx_id, loads whichever NotificationX campaign that id points to, and copies that campaign's own source into the new entry without verifying that the campaign is a Popup Notification or Exit Intent Popup (the two sources this form is intended to serve). This makes it possible for unauthenticated attackers to inject forged social-proof entries (name, title, message, email, theme) into any enabled non-popup NotificationX campaign — WP Comments, WooCommerce/EDD/Give sales, reviews, etc.

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.

CWE-862: Missing Authorization

NotificationX <= 3.3.3 carries this weakness at __return_true, and reaching it takes no account at all. 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 NotificationX the fix is 3.3.4: builds <= 3.3.3 are affected, anything from 3.3.4 onward is not.

Remediation

Update to version 3.3.4, or a newer patched version

How does WordSec protect against this?

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: NotificationX 3.3.4 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

Related records

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