CVE-2026-1926: WooCommerce Subscriptions Auth Bypass Flaw

CVE-2026-1926 Overview

The Subscriptions for WooCommerce plugin for WordPress contains a critical authorization bypass vulnerability due to a missing capability check on the wps_sfw_admin_cancel_susbcription() function. This flaw affects all versions up to and including 1.9.2, allowing unauthenticated attackers to cancel any active WooCommerce subscription without authentication.

The vulnerability stems from the function being hooked directly to the WordPress init action without implementing proper authentication or authorization checks. Additionally, the security implementation only performs a non-empty check on the nonce parameter rather than validating it correctly via wp_verify_nonce(), effectively bypassing WordPress's built-in CSRF protection mechanism.

Critical Impact

Unauthenticated attackers can cancel any active WooCommerce subscription by sending a crafted GET request with an arbitrary nonce value, potentially causing significant business disruption and revenue loss for e-commerce sites.

Affected Products

• Subscriptions for WooCommerce plugin versions up to and including 1.9.2
• WordPress sites running WooCommerce with the vulnerable plugin
• E-commerce sites with active subscription-based products

Discovery Timeline

• 2026-03-18 - CVE-2026-1926 published to NVD
• 2026-03-18 - Last updated in NVD database

Technical Details for CVE-2026-1926

Vulnerability Analysis

This vulnerability represents a Missing Authorization (CWE-862) flaw in the Subscriptions for WooCommerce WordPress plugin. The core issue lies within the wps_sfw_admin_cancel_susbcription() function, which is designed to allow administrators to cancel customer subscriptions but fails to verify the caller's privileges.

The function is registered to WordPress's init action hook, which fires on every page load—including unauthenticated requests. Without proper capability checks using functions like current_user_can(), any visitor can invoke this subscription cancellation functionality.

Compounding this issue, the nonce validation is improperly implemented. Instead of using WordPress's wp_verify_nonce() function to cryptographically validate the nonce token, the code merely checks if the nonce parameter is non-empty. This means an attacker can supply any arbitrary string as a nonce value, completely bypassing the intended CSRF protection.

Root Cause

The root cause is twofold: first, the absence of capability checks to verify that the requesting user has administrative privileges; second, the improper implementation of nonce validation that only checks for the presence of a value rather than verifying its cryptographic validity. This combination allows unauthenticated users to execute administrative functions intended only for authorized site administrators.

Attack Vector

Exploitation requires network access to the WordPress site but no user interaction or authentication. An attacker can craft a simple GET request targeting the vulnerable endpoint with the following parameters:

• A wps_subscription_id parameter containing the target subscription ID
• Any non-empty value for the nonce parameter

The attack is straightforward to execute: an attacker simply needs to enumerate or guess valid subscription IDs and send crafted requests to cancel them. Since subscription IDs are typically sequential integers, mass cancellation attacks are trivially achievable.

Exploitation involves crafting a GET request with an arbitrary nonce value and a target subscription ID. The vulnerable function fails to validate that the requester has administrative privileges, processing the cancellation request regardless of authentication status. For detailed code analysis, refer to the WordPress Plugin Code Reference.

Detection Methods for CVE-2026-1926

Indicators of Compromise

• Unexpected cancellation of WooCommerce subscriptions without administrative action
• HTTP access logs showing GET requests with wps_subscription_id parameters from unknown IP addresses
• Multiple subscription status changes occurring in rapid succession
• Customer complaints about subscriptions being cancelled without their consent
• Unusual spike in subscription cancellation events in WooCommerce activity logs

Detection Strategies

• Monitor web server access logs for GET requests containing wps_subscription_id parameters from unauthenticated sessions
• Implement log correlation to identify bulk subscription cancellation attempts from single IP addresses
• Configure WordPress activity logging to track all subscription status changes with associated user context
• Deploy web application firewall (WAF) rules to flag requests targeting the vulnerable endpoint pattern

Monitoring Recommendations

• Enable detailed logging for WooCommerce subscription state changes
• Set up alerts for subscription cancellations that occur without corresponding administrative user sessions
• Review access logs regularly for patterns of requests containing subscription-related parameters
• Implement rate limiting on requests containing subscription management parameters

How to Mitigate CVE-2026-1926

Immediate Actions Required

• Update the Subscriptions for WooCommerce plugin to a version newer than 1.9.2 immediately
• Review all subscription records for unexpected cancellations that may indicate exploitation
• Temporarily disable the plugin if an immediate update is not possible
• Review web server access logs for evidence of exploitation attempts
• Contact affected customers if unauthorized subscription cancellations are identified

Patch Information

The vulnerability was addressed in versions after 1.9.2. Site administrators should update to the latest available version of the Subscriptions for WooCommerce plugin. The fix implements proper capability checks using current_user_can() and correct nonce validation via wp_verify_nonce(). Review the WordPress Plugin Change Log for detailed patch information. Additional vulnerability details are available from the Wordfence Vulnerability Report.

Workarounds

• Temporarily disable the Subscriptions for WooCommerce plugin until patching is complete
• Implement WAF rules to block GET requests containing the wps_subscription_id parameter
• Restrict access to WordPress admin endpoints using IP whitelisting at the web server level
• Monitor and log all subscription modification requests for forensic analysis

# Apache .htaccess example to block exploitation attempts
RewriteEngine On
RewriteCond %{QUERY_STRING} wps_subscription_id [NC]
RewriteCond %{REMOTE_ADDR} !^192\.168\.1\. [NC]
RewriteRule .* - [F,L]