CVE-2025-11517 is an authorization bypass vulnerability categorized under CWE-639 (Authorization Bypass Through User-Controlled Key) affecting the Event Tickets and Registration plugin for WordPress. The vulnerability arises because the REST API endpoint /wp-json/tribe/tickets/v1/commerce/free/order does not properly verify whether a ticket type is actually free before processing an order. This flaw allows unauthenticated attackers to submit requests that trick the system into granting paid tickets without payment. The plugin versions up to and including 5.26.5 are affected, meaning all prior versions are vulnerable. The vulnerability is exploitable remotely without any authentication or user interaction, making it highly accessible to attackers. The impact is primarily on the integrity of the ticketing system, as attackers can obtain paid tickets for free, causing financial losses to event organizers. The vulnerability does not compromise confidentiality or availability of the system. No patches or official fixes are currently linked, and no known exploits have been reported in the wild as of the publication date. The CVSS v3.1 base score is 7.5, reflecting network attack vector, low attack complexity, no privileges required, no user interaction, unchanged scope, no confidentiality impact, high integrity impact, and no availability impact. The root cause is insufficient authorization checks in the ticket ordering API endpoint, allowing user-controlled input to bypass payment verification.

The primary impact of CVE-2025-11517 is financial loss due to unauthorized acquisition of paid tickets without payment, undermining the revenue model of event organizers using the Event Tickets and Registration plugin. This can lead to significant monetary damage, especially for large-scale events or organizations relying heavily on ticket sales. Additionally, the integrity of the ticketing system is compromised, potentially causing trust issues with customers and damaging the reputation of affected organizations. Since the vulnerability allows unauthenticated remote exploitation, attackers can operate at scale and potentially automate abuse, amplifying the financial impact. Although the vulnerability does not affect system confidentiality or availability, the loss of revenue and erosion of trust can have broader business consequences. Organizations may also face increased support costs and customer dissatisfaction. The lack of authentication and user interaction requirements lowers the barrier to exploitation, increasing the likelihood of attacks once exploit code becomes available.

To mitigate CVE-2025-11517, organizations should immediately update the Event Tickets and Registration plugin to a patched version once available from the vendor. Until a patch is released, administrators can implement the following specific mitigations: 1) Restrict access to the /wp-json/tribe/tickets/v1/commerce/free/order endpoint using web application firewall (WAF) rules or server-level access controls to allow only trusted IP addresses or authenticated users; 2) Monitor and log all requests to this endpoint for unusual activity or spikes in free ticket orders; 3) Implement custom validation hooks or filters in WordPress to enforce payment verification before ticket issuance; 4) Disable or limit the use of free ticket types if not essential; 5) Educate event staff to verify ticket authenticity manually if suspicious activity is detected; 6) Employ rate limiting on the API endpoint to reduce automated abuse attempts. Organizations should also review their event ticketing workflows and consider alternative plugins or solutions with stronger security postures if timely patching is not feasible.