CVE-2025-11770: BrightTALK WordPress Plugin XSS Vulnerability

CVE-2025-11770 Overview

CVE-2025-11770 is a stored cross-site scripting (XSS) vulnerability in the BrightTALK WordPress Shortcode plugin. The flaw affects all versions of the plugin up to and including 2.4.0. The issue resides in the format attribute of the brighttalk-time shortcode, where user-supplied input is neither sanitized on input nor escaped on output. Authenticated users with contributor-level access or higher can inject arbitrary JavaScript into pages. The injected script executes in the browser of any visitor who loads the affected page. The vulnerability is tracked under CWE-79.

Critical Impact
Authenticated contributors can persistently inject JavaScript that executes in every visitor's browser session, enabling session theft, redirection, and administrative account takeover through privilege escalation chains.

Affected Products

BrightTALK WordPress Shortcode plugin versions ≤ 2.4.0
WordPress installations with contributor-level or higher user registration enabled
Any WordPress site rendering pages that contain the brighttalk-time shortcode

Discovery Timeline

2025-11-21 - CVE-2025-11770 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-11770

Vulnerability Analysis

The BrightTALK WordPress Shortcode plugin registers the brighttalk-time shortcode, which accepts a format attribute intended to control date and time rendering. The plugin's shortcode handler concatenates the attribute value directly into HTML output without sanitizing input or escaping output. An authenticated contributor can craft a post containing a brighttalk-time shortcode with a malicious format value carrying arbitrary JavaScript payloads.

Because the payload is stored in the post content and rendered on every page load, the attack persists across sessions and affects every visitor. The scope-changed nature of the flaw means script execution occurs in the context of the site origin, extending reach beyond the vulnerable component. Contributors typically cannot publish posts directly, but administrators and editors previewing or approving content will execute the payload with their own privileges.

Root Cause

The root cause is missing input validation and missing output encoding on the format shortcode attribute. The plugin passes attribute values through to HTML rendering without invoking WordPress escaping helpers such as esc_attr(), esc_html(), or wp_kses(). The vulnerable code path is documented in the WordPress plugin source at line 130.

Attack Vector

Exploitation requires an authenticated account with contributor-level privileges or higher. The attacker creates or edits a post containing the brighttalk-time shortcode and supplies a format attribute carrying HTML or JavaScript such as event handlers on injected tags. When an editor, administrator, or site visitor loads a page containing the shortcode, the browser parses and executes the injected script. Successful exploitation can hijack administrator sessions, exfiltrate cookies, or perform authenticated actions on behalf of the victim. Refer to the Wordfence advisory for additional technical detail.

Detection Methods for CVE-2025-11770

Indicators of Compromise

Posts or pages containing brighttalk-time shortcodes with format attribute values that include <script>, onerror, onload, or other HTML event handlers
New or modified posts authored by contributor-level accounts that reference the BrightTALK shortcode
Outbound HTTP requests from browser sessions to unfamiliar domains immediately after rendering pages containing the shortcode

Detection Strategies

Query the WordPress wp_posts table for post_content values matching the pattern [brighttalk-time combined with suspicious characters in the format argument
Review WordPress audit logs for post creation or edits by contributor accounts targeting pages that embed the shortcode
Inspect rendered HTML for unescaped angle brackets, quotes, or JavaScript URIs originating from shortcode attributes

Monitoring Recommendations

Enable a web application firewall rule to block requests posting shortcode attributes containing HTML tags or JavaScript URIs
Monitor administrator sessions for anomalous requests such as unexpected user creation, plugin installation, or role changes
Alert on Content Security Policy violations reported by browsers viewing content-editor pages

How to Mitigate CVE-2025-11770

Immediate Actions Required

Update the BrightTALK WordPress Shortcode plugin to a version later than 2.4.0 once the vendor publishes a fix
Audit all posts and pages containing the brighttalk-time shortcode and remove any suspicious format attribute values
Review contributor-level accounts and revoke access for any that are unused or unrecognized

Patch Information

At the time of publication, no patched version above 2.4.0 has been confirmed in the referenced advisories. Site owners should monitor the Wordfence advisory and the plugin repository for an official update and apply it as soon as it becomes available.

Workarounds

Deactivate and remove the BrightTALK WordPress Shortcode plugin until a patched version is released
Restrict contributor-level accounts through a role management plugin that prevents shortcode usage in post content
Deploy a Content Security Policy that blocks inline scripts and restricts script sources to trusted origins
Configure a WAF to inspect and reject POST requests containing shortcode attributes with HTML control characters

bash

# Example WordPress CLI query to locate potentially malicious shortcode usage
wp db query "SELECT ID, post_author, post_title FROM wp_posts \
  WHERE post_content REGEXP 'brighttalk-time[^\]]*format=[\"\'][^\"\']*(<|javascript:|on[a-z]+=)'"