CVE intelligence and bounded remediation

CVE-2026-13039 — Eventin security vulnerability

Medium CVSS 5.3

The Eventin – Event Calendar, Event Registration, Tickets & Booking (AI Powered) plugin for WordPress is vulnerable to authorization bypass due to a regression in versions from 4.0.26 up to and including 4.1.15. This is due to the plugin not properly verifying that a user is authorized to perform an action in the payment_complete() function of PaymentController.php. This makes it possible for unauthenticated attackers to mark unpaid ticket orders as completed by submitting a fabricated SureCart checkout ID or FluentCart cart hash, granting themselves paid event access, QR-code attendee tickets, and order confirmation emails without making any real payment. The wp_rest nonce required to reach the vulnerable endpoint is embedded in every public event page, meaning no WordPress session or credentials are needed to obtain it. This vulnerability represents a regression — the same function and endpoint were previously patched but the fix did not persist through subsequent releases.

Severity
Medium
CVSS
5.3 (3.1)
Published
2026-07-10
CISA KEV
Not currently listed
Ecosystem
php/wordpress
Weaknesses
CWE-862

Affected products

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Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

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Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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