CVE-2025-30573 Overview
CVE-2025-30573 is a stored Cross-Site Scripting (XSS) vulnerability in the My Default Post Content WordPress plugin developed by mrdenny. The flaw affects all plugin versions up to and including 0.7.3. It results from improper neutralization of user-supplied input during web page generation, classified under [CWE-79]. An authenticated attacker with high privileges can inject malicious script payloads that persist in the database and execute in the browsers of users who view affected pages. The scope-changed impact means injected scripts can affect resources beyond the vulnerable plugin's security context.
Critical Impact
Authenticated attackers can inject persistent JavaScript payloads that execute in visitors' browsers, enabling session theft, administrative action hijacking, and content defacement across the WordPress site.
Affected Products
- mrdenny My Default Post Content plugin for WordPress
- All versions from initial release through 0.7.3
- WordPress sites with the plugin installed and active
Discovery Timeline
- 2025-03-24 - CVE CVE-2025-30573 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-30573
Vulnerability Analysis
The My Default Post Content plugin allows administrators to configure default text and HTML that populates new WordPress posts. The plugin fails to sanitize or encode input written to its configuration fields before storing it and later rendering it into administrative or post-generation pages. This behavior enables Stored XSS, where an attacker's payload is written once and executed on every subsequent view.
The vulnerability requires an authenticated user with elevated privileges to submit the payload, but the injected script executes in the security context of anyone rendering the affected page. Because the CVSS vector describes a changed scope, the impact extends beyond the vulnerable component and can affect other browser-accessible resources.
Root Cause
The root cause is missing output encoding and inadequate input validation on plugin settings that store post-content templates. WordPress provides functions such as wp_kses, esc_html, and esc_attr to neutralize dangerous markup, but the plugin renders stored template values without applying context-appropriate escaping. Consequently, <script> tags and event-handler attributes survive storage and execute when rendered.
Attack Vector
An attacker who obtains or already holds high-privilege plugin access submits a crafted template value containing JavaScript. The payload persists in the WordPress database. When any authorized user later loads a page that renders the stored template, the browser executes the attacker's script. Exploitation requires user interaction, such as visiting an affected administrative screen or a post populated from the template.
Refer to the Patchstack XSS Vulnerability Report for additional technical detail.
Detection Methods for CVE-2025-30573
Indicators of Compromise
- Unexpected <script>, <iframe>, or on* event handler content stored in wp_options rows related to the my-default-post-content plugin.
- Outbound requests from administrator browsers to unknown domains immediately after visiting post-editor or plugin settings screens.
- New or modified WordPress administrator accounts created shortly after an authenticated session viewed an affected page.
Detection Strategies
- Query the WordPress database for plugin option rows containing HTML tags, event handlers, or JavaScript URI schemes.
- Enable WordPress audit logging to record changes to plugin settings and flag payloads containing script markup.
- Deploy a web application firewall rule to inspect POST bodies to /wp-admin/options.php for XSS signatures targeting this plugin.
Monitoring Recommendations
- Monitor administrator session behavior for anomalous XHR or fetch calls originating from wp-admin pages.
- Alert on any modification to the plugin's stored template values from unexpected source IP addresses or user agents.
- Track plugin version inventory across WordPress sites to identify unpatched installations of my-default-post-content.
How to Mitigate CVE-2025-30573
Immediate Actions Required
- Deactivate the My Default Post Content plugin on all WordPress instances running version 0.7.3 or earlier until a patched release is verified.
- Audit existing plugin settings for stored HTML or script content and remove any unauthorized payloads.
- Rotate WordPress administrator credentials and invalidate active sessions if suspicious activity is observed.
Patch Information
As of the last NVD update on 2026-06-17, no fixed version is listed in the advisory. Consult the Patchstack advisory and the plugin repository for the latest patch status before re-enabling the plugin.
Workarounds
- Restrict high-privilege WordPress roles to a minimal set of trusted administrators to reduce the exploitable population.
- Enforce a Content Security Policy that blocks inline scripts on wp-admin pages to limit payload execution.
- Replace the plugin with an actively maintained alternative that provides equivalent default-content functionality.
# Example: disable the plugin via WP-CLI until a patched version is available
wp plugin deactivate my-default-post-content
wp plugin list --status=active | grep my-default-post-content
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
