CVE-2026-56036: WordPress SimplePay SQL Injection Flaw

CVE-2026-56036 Overview

CVE-2026-56036 is an unauthenticated SQL injection vulnerability affecting the WordPress 워드프레스 결제 심플페이 (SimplePay) plugin, also known as pgall-for-woocommerce, in versions up to and including 5.5.6. The flaw is classified under CWE-89, Improper Neutralization of Special Elements used in an SQL Command. Remote attackers can inject arbitrary SQL statements without authentication. Successful exploitation allows attackers to extract sensitive database content, including customer and payment metadata processed by the WooCommerce integration.

Critical Impact
Unauthenticated attackers can send crafted HTTP requests over the network to execute arbitrary SQL queries against the WordPress database, exposing confidential data and potentially degrading site availability.

Affected Products

WordPress plugin pgall-for-woocommerce (워드프레스 결제 심플페이) versions <= 5.5.6
WooCommerce-based WordPress sites using the SimplePay payment integration
Any deployment exposing the vulnerable plugin endpoints to the internet

Discovery Timeline

2026-06-26 - CVE-2026-56036 published to NVD
2026-06-26 - Last updated in NVD database

Technical Details for CVE-2026-56036

Vulnerability Analysis

The vulnerability resides in the pgall-for-woocommerce plugin, which processes payment-related requests in Korean WooCommerce deployments. User-controlled input reaches SQL query construction without proper sanitization or parameterization. Attackers submit crafted values through HTTP request parameters handled by the plugin, and those values are concatenated directly into database queries. Because authentication is not required, any unauthenticated visitor to the site can trigger the vulnerable code path over the network.

The attack is network-reachable, requires no user interaction, and impacts confidentiality directly. The scope-changed classification indicates that exploitation can affect components beyond the vulnerable plugin, such as other data managed by the shared WordPress database.

Root Cause

The root cause is missing input neutralization on parameters used inside SQL statements. The plugin does not use WordPress prepared statements through $wpdb->prepare() with correct placeholders, or fails to cast and validate expected data types before query construction. This coding pattern permits classic SQL injection payloads to alter query logic.

Attack Vector

Exploitation is performed remotely by sending crafted HTTP requests to plugin endpoints registered by pgall-for-woocommerce. An attacker manipulates parameters such as order identifiers, payment tokens, or filter arguments processed by the plugin. Using UNION-based, boolean-based, or time-based injection payloads, the attacker extracts data from wp_users, wp_usermeta, and WooCommerce order tables. Refer to the Patchstack Vulnerability Report for advisory details.

Detection Methods for CVE-2026-56036

Indicators of Compromise

HTTP requests to pgall-for-woocommerce plugin endpoints containing SQL metacharacters such as ', --, UNION SELECT, SLEEP(, or BENCHMARK(
Unexpected outbound queries to wp_users or wp_usermeta originating from the plugin's PHP process
Elevated response latency on payment-related URIs consistent with time-based blind injection probing
Access log entries from a single source IP enumerating multiple parameter values against plugin endpoints

Detection Strategies

Deploy a web application firewall ruleset that flags SQL injection signatures targeting /wp-content/plugins/pgall-for-woocommerce/ paths and associated AJAX actions
Enable WordPress database query logging and alert on queries containing untypical UNION or comment sequences
Correlate 500-series HTTP responses with subsequent successful 200 responses from the same client to identify injection tuning behavior

Monitoring Recommendations

Aggregate WordPress and reverse proxy logs into a centralized SIEM and apply CWE-89 detection rules against plugin traffic
Monitor MySQL slow query logs for queries whose structure deviates from the plugin's expected statement templates
Track failed and anomalous requests to WooCommerce checkout and payment callback URLs by source IP and user agent

How to Mitigate CVE-2026-56036

Immediate Actions Required

Identify all WordPress sites running pgall-for-woocommerce version 5.5.6 or earlier and remove or disable the plugin until a patched release is confirmed
Restrict access to /wp-admin/ and plugin AJAX endpoints using IP allow-listing where operationally feasible
Rotate WordPress administrator, database, and payment gateway credentials if injection activity is suspected
Review WooCommerce orders and user records for unauthorized reads or modifications

Patch Information

At the time of publication, review the Patchstack Vulnerability Report for the latest fixed version and vendor guidance. Upgrade to a release later than 5.5.6 once the vendor publishes a patched build, and verify plugin integrity after upgrade.

Workarounds

Deploy WAF virtual patching rules that block SQL injection payloads targeting the plugin's request parameters
Temporarily deactivate the pgall-for-woocommerce plugin and disable the SimplePay payment method in WooCommerce settings
Enforce least-privilege on the WordPress database user by revoking unnecessary privileges such as FILE, CREATE, and cross-database access

bash

# Configuration example: disable the vulnerable plugin via WP-CLI
wp plugin deactivate pgall-for-woocommerce
wp plugin status pgall-for-woocommerce