CVE-2026-73398 Overview
CVE-2026-73398 is a broken authentication vulnerability in the Piraeus Bank WooCommerce Payment Gateway plugin version 3.2.0 for WordPress. The flaw allows unauthenticated attackers to bypass authentication controls over the network without user interaction. The issue is categorized under [CWE-288] Authentication Bypass Using an Alternate Path or Channel.
The vulnerability affects WooCommerce stores that rely on the Piraeus Bank payment gateway plugin to process transactions. Successful exploitation impacts the integrity and availability of payment workflow components.
Critical Impact
Unauthenticated attackers can bypass authentication in the Piraeus Bank WooCommerce Payment Gateway plugin, potentially manipulating payment workflow state on affected WordPress stores.
Affected Products
- WordPress sites running WooCommerce
- Piraeus Bank WooCommerce Payment Gateway plugin version 3.2.0
- woo-payment-gateway-for-piraeus-bank WordPress plugin
Discovery Timeline
- 2026-08-18 - CVE-2026-73398 published to NVD
- 2026-08-20 - Last updated in NVD database
Technical Details for CVE-2026-73398
Vulnerability Analysis
The vulnerability resides in the authentication logic of the Piraeus Bank WooCommerce Payment Gateway plugin version 3.2.0. The plugin fails to properly validate requests through its authentication mechanism, allowing an unauthenticated attacker to reach protected functionality. The weakness is classified as [CWE-288], which covers cases where an alternate path or channel bypasses the intended authentication check.
Because the plugin brokers payment gateway interactions between WooCommerce and Piraeus Bank, missing authentication on gateway endpoints can allow attackers to influence transaction state without valid credentials. The attack vector is network-based and requires no user interaction. EPSS data indicates a probability of 0.295% with a percentile of 22.244 as of 2026-08-21.
Root Cause
The root cause is improper enforcement of authentication on one or more plugin endpoints. The plugin exposes functionality that should require an authenticated session or a verified callback signature, but the check can be bypassed or is missing entirely. This falls under the [CWE-288] pattern of authentication bypass using an alternate path or channel.
Attack Vector
An attacker sends crafted HTTP requests directly to the affected plugin endpoints on a vulnerable WordPress site. No credentials, tokens, or user interaction are required. Because the request originates over the network, exploitation can be automated at scale against exposed WooCommerce deployments running the vulnerable plugin version.
See the Patchstack advisory for technical details on the affected endpoints.
Detection Methods for CVE-2026-73398
Indicators of Compromise
- Unauthenticated HTTP requests to plugin endpoints under /wp-content/plugins/woo-payment-gateway-for-piraeus-bank/
- Unexpected WooCommerce order state transitions without corresponding authenticated user sessions
- Payment callback requests from unexpected source IP addresses that do not match Piraeus Bank gateway ranges
Detection Strategies
- Monitor WordPress access logs for anomalous request patterns targeting the woo-payment-gateway-for-piraeus-bank plugin path
- Correlate WooCommerce order events with authenticated user activity to detect state changes lacking a valid session
- Alert on repeated requests to gateway callback URLs from a single unauthenticated source
Monitoring Recommendations
- Enable verbose logging on the WordPress web server and forward events to a centralized SIEM for correlation
- Track plugin version inventory across all WordPress instances to identify hosts running version 3.2.0
- Baseline normal payment callback traffic volumes and alert on deviations
How to Mitigate CVE-2026-73398
Immediate Actions Required
- Identify all WordPress sites running the Piraeus Bank WooCommerce Payment Gateway plugin version 3.2.0
- Apply the vendor-supplied patched version referenced in the Patchstack advisory as soon as it is available
- Restrict access to plugin callback endpoints to known Piraeus Bank source IP ranges at the web server or WAF layer
Patch Information
Refer to the Patchstack advisory for vendor guidance and fixed version details. Administrators should upgrade beyond version 3.2.0 once a patched release is confirmed.
Workarounds
- Temporarily disable the Piraeus Bank WooCommerce Payment Gateway plugin until a patched version is installed
- Deploy a web application firewall rule that blocks unauthenticated requests to plugin endpoints
- Enforce IP allow-listing on payment callback URLs to restrict traffic to legitimate gateway addresses
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
