CVE-2026-57632: Omnisend WooCommerce Auth Bypass Flaw

CVE-2026-57632 Overview

CVE-2026-57632 is a broken access control vulnerability in the Email Marketing for WooCommerce by Omnisend plugin for WordPress. The flaw affects versions up to and including 1.19.0 of the omnisend-connect plugin. Authenticated users with Subscriber-level privileges can access functionality that should be restricted to higher-privileged roles. The issue is classified under CWE-862: Missing Authorization. Exploitation requires an authenticated account but no user interaction, and it can be conducted remotely over the network. The vulnerability was published to the National Vulnerability Database (NVD) on June 26, 2026.

Critical Impact
Authenticated Subscriber-level users can bypass authorization checks in the Omnisend plugin, leading to limited integrity and availability impact on affected WooCommerce stores.

Affected Products

Email Marketing for WooCommerce by Omnisend (omnisend-connect) plugin for WordPress
All versions up to and including 1.19.0
WordPress sites running WooCommerce with the vulnerable plugin installed

Discovery Timeline

2026-06-26 - CVE-2026-57632 published to NVD
2026-06-26 - Last updated in NVD database

Technical Details for CVE-2026-57632

Vulnerability Analysis

The vulnerability stems from missing authorization checks within the Omnisend WooCommerce plugin. One or more plugin endpoints fail to validate whether the requesting user holds the required capability before executing sensitive actions. As a result, any authenticated user, including those with the lowest-privileged Subscriber role, can invoke functionality intended for administrators or shop managers.

Broken access control issues in WordPress plugins typically manifest in AJAX handlers or REST API routes that verify a valid nonce but omit a corresponding current_user_can() capability check. According to the Patchstack advisory, the flaw is exploitable by Subscriber accounts, which are commonly created through open WooCommerce registration.

The recorded EPSS (Exploit Prediction Scoring System) probability is low, and no public proof-of-concept is available at this time.

Root Cause

The root cause is a missing authorization check ([CWE-862]) on plugin actions handled by the omnisend-connect codebase. The plugin does not enforce role or capability verification before executing privileged operations, allowing lower-privileged authenticated sessions to reach protected functionality.

Attack Vector

An attacker must first obtain a Subscriber-level account on the target WordPress site. On stores where open registration is enabled, this step is trivial. Once authenticated, the attacker sends crafted HTTP requests directly to the vulnerable plugin endpoint. Because the endpoint does not verify the caller's capabilities, the request is processed with the elevated logic intended for administrators.

No verified code examples are available. Refer to the Patchstack Vulnerability Database Entry for additional technical context.

Detection Methods for CVE-2026-57632

Indicators of Compromise

Unexpected HTTP POST requests to admin-ajax.php or plugin REST routes originating from Subscriber-level accounts.
Modifications to Omnisend plugin configuration, integration keys, or subscriber lists that cannot be attributed to administrator activity.
New or unusual Subscriber account registrations followed shortly by requests targeting omnisend-connect endpoints.

Detection Strategies

Review WordPress access logs for authenticated requests to Omnisend plugin actions initiated by non-administrative users.
Enable WordPress audit logging plugins to capture role-sensitive actions and correlate them with the initiating user role.
Compare installed plugin versions against 1.19.0 and flag any site still running a vulnerable release.

Monitoring Recommendations

Alert on repeated failed or unusual requests to Omnisend plugin AJAX handlers from low-privilege sessions.
Monitor outbound API traffic from the site to Omnisend endpoints for unexpected volume or configuration changes.
Track new user registrations followed by rapid privileged-action requests within the same session.

How to Mitigate CVE-2026-57632

Immediate Actions Required

Update the Email Marketing for WooCommerce by Omnisend plugin to a version above 1.19.0 as soon as a fixed release is available.
Audit existing Subscriber accounts and remove any that are unrecognized or inactive.
Disable open user registration on WooCommerce sites where it is not strictly required.

Patch Information

Refer to the Patchstack Vulnerability Database Entry for the vendor-supplied fixed version and remediation details. Apply the patched release through the WordPress plugin updater or by replacing the plugin directory with the updated package.

Workarounds

Deactivate the omnisend-connect plugin until a fixed version is installed if the affected functionality is not business-critical.
Restrict access to wp-admin/admin-ajax.php and plugin REST routes at the web application firewall (WAF) layer for non-administrative roles.
Enforce strong registration controls, including CAPTCHA and email verification, to slow automated Subscriber account creation.

bash

# Configuration example: disable open registration and update the plugin via WP-CLI
wp option update users_can_register 0
wp plugin update omnisend-connect
wp plugin list --name=omnisend-connect --fields=name,status,version