CVE-2026-13390 in The Events Calendar Plugin
Summary
by MITRE • 07/27/2026
The Events Calendar WordPress plugin before 6.16.5.1 does not perform an authorization check on one of its Event Aggregator import REST API routes and skips an integrity check for a particular status value, allowing unauthenticated attackers to mark existing import records as failed and to store arbitrary content in a hidden comment record.
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Analysis
by VulDB Data Team • 07/27/2026
The vulnerability resides within the Events Calendar WordPress plugin version 6.16.5.1 and earlier, where insufficient authorization controls exist on a specific Event Aggregator import REST API endpoint. This weakness creates a critical security gap that allows unauthenticated attackers to manipulate import records and inject arbitrary content into hidden comment fields. The flaw stems from the absence of proper authentication verification on one of the plugin's REST API routes dedicated to event aggregation functionality, which is commonly used for importing calendar events from external sources.
The technical implementation of this vulnerability involves two primary components that compound the security risk. First, the plugin fails to validate user authorization before processing requests to a specific Event Aggregator import route, effectively removing any authentication barriers that should normally protect administrative functions. Second, the system neglects to perform integrity checks on a particular status value field within the import records, allowing attackers to manipulate the status without proper validation. This dual failure enables malicious actors to mark existing import records as failed, potentially disrupting legitimate event imports and creating false error conditions that could go unnoticed by administrators.
The operational impact of this vulnerability extends beyond simple data manipulation, as it creates persistent security risks within WordPress installations using the affected plugin version. Attackers can exploit this weakness to inject arbitrary content into hidden comment records, which may contain sensitive information or serve as potential vectors for further exploitation. The ability to mark import records as failed can cause legitimate event imports to be marked incorrectly, leading to operational disruptions and potentially masking actual import failures that require attention. This vulnerability particularly affects organizations relying on automated event aggregation processes, where the false status indicators could result in missed events or incorrect scheduling information.
Security mitigations for this vulnerability should focus on immediate patching of the Events Calendar plugin to version 6.16.5.1 or later, which addresses both the authorization bypass and integrity check deficiencies. Organizations should also implement monitoring of REST API endpoints for unusual access patterns and unauthorized status modifications. The vulnerability aligns with CWE-863 (Authorization Bypass Through User-Controlled Key) and CWE-20 (Improper Input Validation), while its exploitation techniques correspond to ATT&CK tactics including T1078 (Valid Accounts) and T1566 (Phishing). Administrators should also consider implementing additional security controls such as API rate limiting, enhanced logging of administrative actions, and regular security audits of WordPress plugins to identify similar authorization gaps in other third-party components.