CVE-2025-49321: Eventin wp-event-solution XSS Vulnerability

CVE-2025-49321 Overview

CVE-2025-49321 is a reflected Cross-Site Scripting (XSS) vulnerability in the Arraytics Eventin plugin (wp-event-solution) for WordPress. The flaw affects all versions of Eventin up to and including 4.0.28. It stems from improper neutralization of user-supplied input during web page generation, tracked as [CWE-79].

The vulnerability requires user interaction, such as clicking a crafted link, but does not require authentication. Successful exploitation runs attacker-controlled JavaScript in the victim's browser session against the WordPress site. This can lead to session theft, forced actions, or delivery of secondary payloads.

Critical Impact

Attackers can execute arbitrary JavaScript in a victim's browser context, enabling session hijacking, credential theft, and unauthorized actions against WordPress sites running vulnerable Eventin installations.

Affected Products

• Themewinter Eventin (wp-event-solution) plugin for WordPress
• All versions from initial release through 4.0.28
• WordPress sites with the Eventin event management plugin installed and active

Discovery Timeline

• 2025-06-27 - CVE-2025-49321 published to NVD
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-49321

Vulnerability Analysis

The Eventin plugin fails to sanitize or encode user-supplied input before reflecting it back in generated HTML responses. When a user visits a URL containing a malicious payload, the plugin renders that payload directly into the page. The browser then interprets the payload as executable script.

This is a reflected XSS pattern, meaning the payload is delivered per request rather than stored on the server. The attack requires the victim to interact with a crafted URL or form submission. Because the scope changes to the victim's authenticated session, an attacker can act on behalf of authenticated administrators who click the link.

Root Cause

The root cause is missing output encoding and input validation in one or more request handlers within wp-event-solution. Parameters accepted from HTTP requests are echoed back into HTML contexts without applying WordPress escaping functions such as esc_html(), esc_attr(), or wp_kses(). This omission allows raw HTML and JavaScript to be injected into the rendered response.

Attack Vector

Exploitation occurs over the network without authentication. An attacker crafts a URL pointing to a vulnerable Eventin endpoint and embeds a JavaScript payload in a reflected parameter. The attacker then delivers the URL via phishing email, forum post, or social media. When a WordPress user opens the link, the payload executes in their browser under the site's origin.

The vulnerability manifests in request parameter handling within Eventin's front-end or admin endpoints. See the Patchstack Vulnerability Report for advisory details.

Detection Methods for CVE-2025-49321

Indicators of Compromise

• HTTP requests to Eventin plugin endpoints containing URL-encoded <script>, javascript:, onerror=, or onload= tokens in query parameters
• Referer headers originating from external domains that redirect users into WordPress admin URLs containing Eventin paths
• Unexpected outbound requests from browser sessions to attacker-controlled domains after visiting WordPress pages
• New or modified administrator accounts or plugin settings created shortly after an admin visited a crafted link

Detection Strategies

• Inspect web server access logs for suspicious query strings hitting /wp-content/plugins/wp-event-solution/ or Eventin shortcode-rendered pages
• Deploy a Web Application Firewall (WAF) rule that blocks reflected XSS patterns in parameters submitted to Eventin endpoints
• Correlate browser-side Content Security Policy (CSP) violation reports with server request logs to identify injection attempts

Monitoring Recommendations

• Enable verbose logging on the WordPress reverse proxy and forward logs to a centralized analytics platform for XSS pattern searches
• Alert on any HTTP 200 response where the request query string contains encoded angle brackets and the response body reflects them unescaped
• Track plugin version inventory across WordPress fleets and alert when hosts run Eventin <= 4.0.28

How to Mitigate CVE-2025-49321

Immediate Actions Required

• Upgrade the Eventin plugin to a version newer than 4.0.28 as soon as a fixed release is available from the vendor
• Audit WordPress administrator activity logs for signs of unauthorized configuration changes since the plugin was installed
• Force password resets and session invalidation for administrators who may have clicked untrusted links pointing at the site

Patch Information

Refer to the Patchstack Vulnerability Report for the current patch status and vendor advisory. Apply the fixed version through the WordPress plugin updater or by replacing the plugin files manually.

Workarounds

• Deactivate the Eventin plugin until a patched version is installed if event management functionality is not business critical
• Enforce a strict Content Security Policy that disallows inline scripts and restricts script sources to trusted origins
• Restrict access to WordPress admin pages by IP allowlist to reduce the pool of administrators exposed to phishing-delivered XSS links

# Example Content Security Policy header to limit XSS impact
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'"