CVE-2025-30613 Overview
CVE-2025-30613 is a stored cross-site scripting (XSS) vulnerability in the N-Media Nmedia MailChimp WordPress plugin (nmedia-mailchimp-widget). The flaw affects all versions up to and including 5.4. It stems from improper neutralization of user-supplied input during web page generation, tracked as [CWE-79]. An authenticated attacker with low privileges can inject malicious scripts that persist in the application and execute in the browsers of other users who view the affected pages. The issue is scoped as changed, meaning payloads can affect resources beyond the vulnerable component.
Critical Impact
Authenticated attackers can inject persistent JavaScript payloads that execute in administrator and visitor browsers, enabling session theft, unauthorized actions, and site defacement.
Affected Products
- N-Media Nmedia MailChimp WordPress plugin (nmedia-mailchimp-widget) versions up to and including 5.4
- WordPress sites that install and activate the affected plugin
- Administrative and visitor-facing pages rendering plugin output
Discovery Timeline
- 2025-04-01 - CVE-2025-30613 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-30613
Vulnerability Analysis
The plugin fails to sanitize or encode user-controlled input before rendering it into HTML output. When an authenticated user submits data through a vulnerable field, the plugin stores the raw payload and later reflects it in generated pages without proper escaping. Because the payload persists in the site database, every request that renders the affected view triggers the injected script. The changed scope indicates that the injected code executes in a security context distinct from the vulnerable component, which broadens the reach of a successful attack. User interaction is required, since a victim must load a page containing the stored payload.
Root Cause
The root cause is missing output encoding on data flowing from plugin input handlers into HTML sinks. Trusted WordPress escaping functions such as esc_html(), esc_attr(), or wp_kses_post() are either absent or applied inconsistently. Combined with permissive input validation, this allows raw <script> tags, event handlers, and other HTML constructs to be persisted verbatim.
Attack Vector
Exploitation requires network access, low privileges, and user interaction. An attacker with a low-privileged account submits a crafted payload through a plugin input field that is stored server-side. When an administrator or another user views the page rendering that content, the browser executes the attacker-controlled JavaScript. Typical outcomes include session token exfiltration, forced administrative actions through admin-ajax.php, creation of rogue administrator accounts, and injection of SEO spam or malicious redirects. Refer to the Patchstack XSS Vulnerability Advisory for advisory-level detail.
Detection Methods for CVE-2025-30613
Indicators of Compromise
- Unexpected <script>, onerror, onload, or javascript: fragments stored in wp_options, wp_postmeta, or plugin-specific tables.
- Administrator sessions initiating unusual wp-admin requests such as user creation, plugin installation, or theme edits shortly after viewing plugin-managed pages.
- Outbound requests from browsers to unfamiliar domains sourced from pages that render Nmedia MailChimp widget content.
Detection Strategies
- Review plugin input handlers and database rows for HTML tags or JavaScript event attributes in fields that should contain plain text.
- Deploy web application firewall rules that identify XSS payload patterns targeting plugin admin-post.php and admin-ajax.php endpoints.
- Correlate WordPress audit logs with proxy logs to detect script execution originating from stored content.
Monitoring Recommendations
- Enable a WordPress activity logging plugin to record option updates, user role changes, and content modifications.
- Monitor Content Security Policy (CSP) violation reports for inline script executions on plugin-rendered pages.
- Alert on the creation of new administrator accounts, changes to siteurl or home, and installation of unexpected plugins.
How to Mitigate CVE-2025-30613
Immediate Actions Required
- Deactivate the Nmedia MailChimp plugin on any site running version 5.4 or earlier until a patched release is confirmed installed.
- Audit user accounts and remove any unexpected administrator or editor accounts created during the exposure window.
- Rotate credentials, API keys, and session tokens for privileged WordPress users who may have viewed injected content.
Patch Information
The vendor advisory tracked by Patchstack lists all versions up to and including 5.4 as affected. Site owners should upgrade to a release later than 5.4 once published by N-Media. Confirm the fixed version by consulting the Patchstack XSS Vulnerability Advisory and the plugin repository entry before deploying to production.
Workarounds
- Remove the plugin entirely if no patched version is available and the widget functionality is not business-critical.
- Restrict access to plugin configuration by limiting the WordPress roles able to submit input to the vulnerable fields.
- Enforce a strict Content Security Policy that blocks inline scripts and unknown script sources to reduce impact of stored payloads.
# Configuration example: disable the plugin via WP-CLI until a patch is applied
wp plugin deactivate nmedia-mailchimp-widget
wp plugin status nmedia-mailchimp-widget
# Optional: remove the plugin after backing up any required configuration
wp plugin uninstall nmedia-mailchimp-widget
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.