CVE-2025-5936 Overview
CVE-2025-5936 affects the VR Calendar plugin for WordPress in all versions up to and including 2.4.7. The vulnerability is a Cross-Site Request Forgery (CSRF) flaw caused by missing or incorrect nonce validation on the syncCalendar() function. Unauthenticated attackers can trigger a calendar sync by forging a request, provided they can trick a site administrator into clicking a crafted link. The issue is tracked under [CWE-352]. The flaw does not directly expose confidential data but permits low-impact integrity changes to the affected WordPress site.
Critical Impact
Attackers can trigger unauthorized calendar synchronization on affected WordPress sites by social-engineering an administrator into visiting a malicious URL.
Affected Products
- VR Calendar plugin for WordPress, all versions through 2.4.7
- WordPress sites running vr-calendar-sync with vulnerable VRCalendarAdmin.class.php
- Deployments where administrators can be reached via phishing or malicious links
Discovery Timeline
- 2025-06-27 - CVE-2025-5936 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-5936
Vulnerability Analysis
The VR Calendar plugin exposes an administrative syncCalendar() action that lacks proper nonce verification. WordPress uses nonces as anti-CSRF tokens to confirm that a state-changing request originated from the authorized user interface. Without this check, the plugin cannot distinguish between an intentional administrator action and a forged cross-origin request. An attacker who lures an authenticated administrator to a malicious page can cause the browser to submit the sync request using the administrator's active session cookies. The vulnerable code path is documented in the plugin's Admin/Classes/VRCalendarAdmin.class.php file, referenced by the WordPress Plugin File Review.
Root Cause
The root cause is missing or incorrect nonce validation on the syncCalendar() handler. WordPress plugins are expected to invoke check_admin_referer() or wp_verify_nonce() before performing privileged actions. The VR Calendar plugin omits or misimplements this check, leaving the endpoint reachable through forged requests.
Attack Vector
Exploitation requires user interaction from an authenticated administrator. The attacker hosts a page or crafts a link that issues a request to the vulnerable endpoint. When the administrator visits the page while logged in, the browser attaches session cookies and the sync operation executes. No credentials are required from the attacker, but the impact is limited to integrity changes tied to calendar sync functionality. Additional technical detail is available in the Wordfence Vulnerability Report.
No verified proof-of-concept code is publicly available for this vulnerability. Refer to the plugin source and vendor advisory linked above for the affected code path.
Detection Methods for CVE-2025-5936
Indicators of Compromise
- Unexpected calendar synchronization events in WordPress admin logs or plugin activity logs
- Referer headers on syncCalendar() requests originating from external or unrelated domains
- Administrator sessions performing sync actions immediately after visiting untrusted URLs
Detection Strategies
- Inspect web server access logs for requests targeting the VR Calendar admin action with off-site referers
- Correlate administrator browsing activity with plugin state changes to identify forged requests
- Deploy a web application firewall rule that flags state-changing requests to vr-calendar-sync endpoints lacking a valid nonce parameter
Monitoring Recommendations
- Enable WordPress audit logging to capture admin-triggered plugin actions and the source IP for each event
- Monitor for anomalous outbound HTTP requests from the WordPress host that follow a sync trigger
- Alert on administrator accounts loading pages with cross-origin POST or GET redirects to wp-admin endpoints
How to Mitigate CVE-2025-5936
Immediate Actions Required
- Update the VR Calendar plugin to a version later than 2.4.7 once the vendor releases a patched release
- Restrict administrator browsing to trusted sites and require separate browser profiles for WordPress administration
- Deploy web application firewall protections that enforce nonce presence on state-changing plugin endpoints
Patch Information
As of the last NVD update on 2026-06-17, no fixed version is listed in the enriched data. Site owners should consult the Wordfence Vulnerability Report and the WordPress plugin repository for the latest fix status and version guidance.
Workarounds
- Disable or uninstall the VR Calendar plugin until a patched version is confirmed available
- Enforce SameSite=Strict cookie attributes on WordPress session cookies where feasible to reduce CSRF exposure
- Require administrators to log out of WordPress before browsing external content and use browser isolation for admin sessions
# Configuration example: disable the vulnerable plugin via WP-CLI
wp plugin deactivate vr-calendar-sync
wp plugin delete vr-calendar-sync
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
