CVE-2026-24363: WP Cost Estimation Auth Bypass Flaw

CVE-2026-24363 Overview

CVE-2026-24363 is a Missing Authorization vulnerability affecting the WP Cost Estimation & Payment Forms Builder plugin (WP_Estimation_Form) developed by loopus. This vulnerability allows attackers to exploit incorrectly configured access control security levels, potentially enabling unauthorized access to sensitive functionality and data within WordPress installations running the vulnerable plugin.

The vulnerability stems from broken access control mechanisms that fail to properly verify user authorization before permitting access to protected resources or functionality. Attackers can leverage this flaw to bypass intended security restrictions without authentication.

Critical Impact

Unauthenticated attackers can exploit this missing authorization vulnerability over the network to gain unauthorized access to sensitive information, potentially exposing confidential business data, customer information, and form submissions.

Affected Products

• WP Cost Estimation & Payment Forms Builder versions prior to 10.3.0
• WordPress installations with the WP_Estimation_Form plugin

Discovery Timeline

• 2026-03-25 - CVE CVE-2026-24363 published to NVD
• 2026-03-26 - Last updated in NVD database

Technical Details for CVE-2026-24363

Vulnerability Analysis

This vulnerability is classified under CWE-862 (Missing Authorization), which occurs when a software application does not perform authorization checks when an actor attempts to access a resource or execute an action. In the context of WP Cost Estimation & Payment Forms Builder, the plugin fails to implement proper capability checks on certain AJAX endpoints or administrative functions.

The attack can be executed remotely over the network without requiring any prior authentication or user interaction. Successful exploitation results in unauthorized disclosure of confidential information, though the vulnerability does not appear to allow modification of data or system disruption based on the available information.

Root Cause

The root cause of this vulnerability is the absence of proper authorization checks within the WP_Estimation_Form plugin. WordPress plugins typically implement capability checks using functions like current_user_can() to verify that the requesting user has appropriate permissions before executing sensitive operations. When these checks are missing or improperly implemented, attackers can access restricted functionality.

The affected plugin likely exposes AJAX handlers or REST API endpoints that process requests without validating whether the requesting user has the necessary privileges to perform the requested action.

Attack Vector

The vulnerability is exploited over a network-based attack vector. An unauthenticated attacker can send specially crafted HTTP requests to the vulnerable WordPress site targeting the WP_Estimation_Form plugin's endpoints. Since no authentication is required and the attack complexity is low, exploitation is straightforward for attackers who identify vulnerable installations.

The attack flow typically involves:

1. Identifying WordPress sites running vulnerable versions of WP Cost Estimation & Payment Forms Builder
2. Sending direct requests to unprotected plugin endpoints
3. Receiving sensitive data or accessing restricted functionality without proper authorization

For detailed technical information about this vulnerability, refer to the Patchstack WP Cost Estimation Vulnerability advisory.

Detection Methods for CVE-2026-24363

Indicators of Compromise

• Unusual or unauthorized access to WP Cost Estimation & Payment Forms Builder plugin endpoints
• Unexpected AJAX requests to plugin-specific endpoints from unauthenticated sessions
• Log entries showing access to form data or configuration settings without corresponding authenticated user sessions
• Suspicious requests containing plugin-specific parameters from external IP addresses

Detection Strategies

• Review web server access logs for requests targeting /wp-admin/admin-ajax.php with actions related to lfb_ or estimation form parameters from unauthenticated sources
• Implement Web Application Firewall (WAF) rules to monitor and alert on suspicious activity targeting the WP_Estimation_Form plugin
• Deploy WordPress security plugins capable of detecting broken access control attempts
• Monitor for bulk data extraction attempts or rapid sequential requests to plugin endpoints

Monitoring Recommendations

• Enable detailed logging for WordPress AJAX requests and review logs regularly for anomalous patterns
• Set up alerts for high-volume requests to plugin endpoints, which may indicate automated exploitation attempts
• Implement rate limiting on plugin endpoints to slow down potential data exfiltration
• Use SentinelOne Singularity Platform to monitor endpoint activity and detect unauthorized access patterns

How to Mitigate CVE-2026-24363

Immediate Actions Required

• Update WP Cost Estimation & Payment Forms Builder to version 10.3.0 or later immediately
• Audit access logs to determine if the vulnerability has been exploited prior to patching
• Review any sensitive data that may have been exposed through the plugin's forms and notify affected parties if necessary
• Consider temporarily disabling the plugin if an immediate update is not possible

Patch Information

The vulnerability has been addressed in WP Cost Estimation & Payment Forms Builder version 10.3.0. Site administrators should update to this version or later through the WordPress plugin update mechanism. The patch implements proper authorization checks to ensure that only authenticated users with appropriate capabilities can access protected functionality.

For more information, see the Patchstack WP Cost Estimation Vulnerability advisory.

Workarounds

• If immediate patching is not possible, restrict access to admin-ajax.php endpoints related to the plugin via .htaccess rules or server configuration
• Implement IP-based access restrictions to limit exposure while preparing for the update
• Use a Web Application Firewall to block unauthorized requests to vulnerable endpoints
• Consider disabling the plugin temporarily if it is not critical to business operations

# WordPress plugin update via WP-CLI
wp plugin update wp-cost-estimation-payment-forms-builder --version=10.3.0

# Verify plugin version after update
wp plugin get wp-cost-estimation-payment-forms-builder --field=version

# Example .htaccess restriction for wp-admin/admin-ajax.php (temporary workaround)
# Add to WordPress root .htaccess if immediate patching is not possible
# <Files admin-ajax.php>
#   Order allow,deny
#   Allow from 192.168.1.0/24
#   Deny from all
# </Files>