CVE-2025-11517 is an authorization bypass vulnerability categorized under CWE-639, affecting the Event Tickets and Registration plugin for WordPress, versions up to and including 5.26.5. The vulnerability arises from the /wp-json/tribe/tickets/v1/commerce/free/order REST API endpoint, which does not properly verify whether a ticket type is free before processing an order. This flaw allows unauthenticated attackers to submit requests that bypass payment requirements and obtain paid tickets without paying. The root cause is insufficient authorization checks on user-controlled keys that determine ticket pricing. Since the endpoint is accessible without authentication and requires no user interaction, exploitation is straightforward and can be automated. The impact is primarily financial, as attackers can acquire paid tickets for free, resulting in revenue loss for event organizers. The vulnerability does not affect confidentiality or availability but severely impacts integrity by allowing unauthorized access to paid resources. No patches or exploit code are currently publicly available, but the vulnerability has been officially published and assigned a CVSS v3.1 score of 7.5 (high severity) due to its ease of exploitation and significant impact on integrity. Organizations using this plugin for event ticketing should prioritize mitigation to prevent unauthorized ticket acquisition.

For European organizations, especially those relying on WordPress-based event management systems, this vulnerability poses a direct financial threat through loss of ticket sales revenue. Event organizers, venues, and promoters using the Event Tickets and Registration plugin could face unauthorized access to paid tickets, undermining their business models. The vulnerability could also damage customer trust if ticket availability is manipulated or if events become oversubscribed due to fraudulent ticket acquisition. While the vulnerability does not compromise user data confidentiality or system availability, the integrity breach can disrupt event operations and financial planning. Additionally, organizations may incur costs related to incident response, forensic analysis, and potential reputational damage. Given the widespread use of WordPress in Europe and the popularity of the plugin, the threat could affect a broad range of small to medium-sized enterprises and large event organizers alike.

1. Monitor the vendor’s official channels for a security patch and apply updates immediately once available. 2. Until a patch is released, implement web application firewall (WAF) rules to restrict or monitor access to the /wp-json/tribe/tickets/v1/commerce/free/order endpoint, especially from unauthenticated sources. 3. Employ rate limiting and anomaly detection on ticket purchase endpoints to identify and block suspicious activity indicative of payment bypass attempts. 4. Conduct regular audits of ticket sales and reconcile with payment records to detect discrepancies early. 5. Consider disabling or restricting the REST API endpoints related to ticket ordering if not essential for business operations. 6. Educate event management teams about the vulnerability and encourage vigilance for unusual ticketing patterns. 7. Use multi-factor authentication and role-based access controls for administrative interfaces to reduce the risk of further exploitation.