CVE-2025-58861: Quick Event Calendar CSRF Vulnerability

CVE-2025-58861 Overview

CVE-2025-58861 is a Cross-Site Request Forgery (CSRF) vulnerability in the WP Corner Quick Event Calendar plugin for WordPress. The flaw allows an attacker to trigger Stored Cross-Site Scripting (XSS) through forged requests. The vulnerability affects all versions of the quick-event-calendar plugin up to and including 1.4.9. The weakness is classified under [CWE-352]. Successful exploitation requires user interaction, typically tricking an authenticated administrator into visiting a malicious page. Once triggered, attacker-controlled script content is stored in the plugin and executed in the browser context of subsequent visitors.

Critical Impact
An unauthenticated attacker can persist malicious JavaScript into a WordPress site by abusing missing CSRF protections, leading to stored XSS execution against site administrators and visitors.

Affected Products

WP Corner Quick Event Calendar plugin for WordPress
All plugin versions from n/a through 1.4.9
WordPress sites with the quick-event-calendar plugin installed and active

Discovery Timeline

2025-09-05 - CVE-2025-58861 published to NVD
2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-58861

Vulnerability Analysis

The Quick Event Calendar plugin exposes state-changing actions without validating that the request originates from a legitimate, authenticated session. The plugin does not enforce anti-CSRF nonce checks on endpoints that accept event data. As a result, an attacker can craft a malicious web page that submits a forged request to a vulnerable WordPress site. If an authenticated administrator visits the attacker's page, the browser issues the request using the administrator's session cookies. The forged request stores attacker-supplied content, including JavaScript payloads, into the plugin's data. Because the stored content is later rendered without sufficient output encoding, the injected script executes in the context of any user viewing the calendar. This chains a CSRF defect with a Stored XSS sink, expanding the impact from a single forged action to persistent script execution. The attack is network reachable, requires no privileges on the target site, and depends on user interaction with a malicious link.

Root Cause

The root cause is missing or insufficient request origin validation, as defined by [CWE-352]. WordPress provides wp_nonce_field() and check_admin_referer() primitives that the plugin fails to apply consistently on endpoints handling event creation or modification. Output rendering also fails to escape stored content, allowing the chained Stored XSS.

Attack Vector

An attacker hosts a page containing a hidden form or fetch() call targeting the vulnerable plugin endpoint. The attacker lures an authenticated WordPress administrator to the page through phishing, comment links, or social engineering. The victim's browser submits the forged request with valid session cookies, and the plugin stores attacker-controlled markup. Subsequent page views render the payload, executing arbitrary JavaScript in the victim's browser session.

No verified proof-of-concept code is published for this issue. Refer to the Patchstack Vulnerability Report for advisory details.

Detection Methods for CVE-2025-58861

Indicators of Compromise

Unexpected <script>, onerror, or onload attributes appearing inside stored calendar event titles, descriptions, or metadata.
New or modified calendar events created outside normal administrative workflows or from unfamiliar source IP addresses.
HTTP POST or admin-ajax requests to Quick Event Calendar endpoints with Referer headers pointing to external, non-trusted origins.
Browser console errors or outbound network calls to attacker-controlled domains originating from pages that render the calendar.

Detection Strategies

Inspect the WordPress database tables used by quick-event-calendar for HTML tags or JavaScript event handlers in event content fields.
Review web server access logs for requests to plugin endpoints lacking valid wp_nonce parameters or with cross-origin Referer values.
Enable a Content Security Policy (CSP) in report-only mode to surface inline script execution sourced from calendar pages.

Monitoring Recommendations

Alert on administrator session activity that triggers content-creation endpoints immediately after navigating to external links.
Monitor file integrity and database changes for the quick-event-calendar plugin tables and option keys.
Track WordPress audit logs for event creation or update actions performed without a corresponding authenticated admin UI session.

How to Mitigate CVE-2025-58861

Immediate Actions Required

Identify all WordPress sites running the Quick Event Calendar plugin and confirm the installed version against 1.4.9 or earlier.
Update the plugin to a fixed release as soon as the vendor publishes one; consult the Patchstack Vulnerability Report for status.
Audit existing calendar entries for injected scripts and remove any malicious content before restoring service.
Rotate administrator credentials and invalidate active sessions if forged requests are suspected.

Patch Information

At the time of publication, the advisory lists affected versions through 1.4.9 with no confirmed fixed version in the enriched data. Site operators should monitor the WordPress plugin repository and the Patchstack Vulnerability Report for an updated release that introduces nonce validation and output escaping.

Workarounds

Deactivate and remove the Quick Event Calendar plugin until a patched version is available.
Restrict administrator browsing sessions by isolating WordPress administration in a dedicated browser profile to reduce CSRF exposure.
Deploy a Web Application Firewall (WAF) rule that blocks state-changing requests to plugin endpoints lacking a valid same-origin Referer header.
Enforce a strict Content Security Policy that disallows inline scripts on pages rendering calendar content.

bash

# Example: temporarily deactivate the plugin via WP-CLI
wp plugin deactivate quick-event-calendar
wp plugin delete quick-event-calendar