CVE-2026-111957: SUMIT Payment Gateway Auth Bypass Flaw

CVE-2026-111957 Overview

CVE-2026-111957 affects the SUMIT Payment Gateway for WooCommerce WordPress plugin in versions prior to 4.0.0. The plugin fails to bind confirmed payments to the originating order and does not validate the payment amount against the order total. Unauthenticated attackers can replay a payment identifier obtained from any legitimate transaction to mark pending orders as paid. The flaw is categorized under CWE-863: Incorrect Authorization. Merchants running vulnerable installations risk shipping goods or releasing services without receiving corresponding funds.

Critical Impact

Unauthenticated attackers can mark pending WooCommerce orders as paid by replaying a valid payment identifier, resulting in order fulfillment without payment.

Affected Products

• SUMIT Payment Gateway for WooCommerce WordPress plugin versions prior to 4.0.0
• WordPress sites running WooCommerce with the SUMIT gateway enabled
• Online merchants accepting SUMIT-processed payments through WooCommerce checkout

Discovery Timeline

• 2026-10-21 - CVE-2026-111957 published to NVD
• 2026-10-21 - Last updated in NVD database

Technical Details for CVE-2026-111957

Vulnerability Analysis

The SUMIT Payment Gateway plugin processes payment confirmations without enforcing a cryptographic or logical binding between the payment identifier returned by the provider and the WooCommerce order it is meant to settle. The confirmation handler accepts a payment identifier, queries the provider for its status, and marks the referenced order as paid when the identifier corresponds to any successful transaction. The handler does not verify that the payment identifier was issued for the specific order under review. It also omits a comparison between the amount captured and the WooCommerce order total.

This combination allows a single genuine payment, including one made by the attacker for a low-value item, to be replayed as proof of payment for any pending order on the storefront. The endpoint is reachable without authentication, so no account on the target site is required.

Root Cause

The root cause is an authorization logic flaw [CWE-863]. The plugin trusts the payment identifier as sufficient proof of payment for the current order rather than tying the provider-side transaction to a server-generated nonce or order reference. Missing amount validation compounds the issue by permitting any value, including a trivial one, to settle a high-value order.

Attack Vector

The attack is network-based and unauthenticated. An attacker completes one real purchase through a store using the SUMIT gateway to obtain a valid payment identifier. The attacker then creates pending orders on any vulnerable site and submits the captured identifier to the plugin's confirmation endpoint. The target site contacts SUMIT, observes a successful payment status, and transitions the order to paid.

No exploit code is required beyond standard HTTP requests to the WooCommerce checkout and payment confirmation routes. Technical details are available in the WPScan Vulnerability Report.

Detection Methods for CVE-2026-111957

Indicators of Compromise

• • WooCommerce orders transitioning to a paid state while the recorded payment amount does not match the order total.
• • Multiple orders across one or more stores sharing the same SUMIT payment identifier in the order metadata.
• • Repeated hits to the SUMIT payment confirmation callback endpoint from a small set of IP addresses or user agents.
• • Fulfillment events for high-value orders preceded by only a single low-value transaction from the same customer profile.

Detection Strategies

• • Audit WooCommerce order metadata for duplicate transaction_id or SUMIT reference values across distinct orders.
• • Correlate the amount reported by SUMIT with the WooCommerce order total and flag mismatches for manual review.
• • Review web server logs for unauthenticated POST requests to the SUMIT confirmation route followed by rapid order status changes.

Monitoring Recommendations

• • Enable WooCommerce order status change logging and forward events to a centralized log platform for correlation.
• • Alert on order fulfillment where the paid amount is less than the order total or where no provider webhook preceded the status change.
• • Monitor plugin version inventories across managed WordPress fleets and alert when SUMIT Payment Gateway versions below 4.0.0 are present.

How to Mitigate CVE-2026-111957

Immediate Actions Required

• • Upgrade the SUMIT Payment Gateway for WooCommerce plugin to version 4.0.0 or later on all affected sites.
• • Review recent orders processed by the SUMIT gateway for amount mismatches and duplicate payment identifiers, and reverse fulfillment for confirmed abuse.
• • Reconcile WooCommerce order records against SUMIT merchant transaction reports to identify unmatched settlements.

Patch Information

The vendor addressed the flaw in SUMIT Payment Gateway for WooCommerce version 4.0.0. The fixed release binds payment identifiers to the originating order and validates the captured amount against the WooCommerce order total before marking the order as paid. Refer to the WPScan Vulnerability Report for advisory details.

Workarounds

• • Disable the SUMIT Payment Gateway plugin until the site can be updated to version 4.0.0 or later.
• • Switch WooCommerce to an alternate payment gateway that validates order and amount binding server-side.
• • Place pending orders in a manual review queue so staff verify payment amounts against provider records before fulfillment.

# Configuration example
# Update the plugin using WP-CLI on affected WordPress hosts
wp plugin update sumit-payment-gateway-for-woocommerce --version=4.0.0

# Verify installed version
wp plugin get sumit-payment-gateway-for-woocommerce --field=version

# Temporary mitigation: deactivate the plugin until patched
wp plugin deactivate sumit-payment-gateway-for-woocommerce