CVE-2025-3435: Mang Board WP Plugin XSS Vulnerability

CVE-2025-3435 Overview

The Mang Board WP plugin for WordPress contains a Stored Cross-Site Scripting (XSS) vulnerability [CWE-79] affecting all versions up to and including 1.8.6. The flaw resides in the board_header and board_footer parameters, which lack proper input sanitization and output escaping. Authenticated attackers with administrator-level access can inject arbitrary web scripts into pages. Injected scripts execute in the browser of any user who visits the affected page. The vulnerability only impacts multi-site installations and installations where the unfiltered_html capability has been disabled.

Critical Impact

Authenticated administrators on multi-site WordPress installations can inject persistent JavaScript payloads that execute in visitor browsers, enabling session theft, defacement, or privilege abuse against super-admin accounts.

Affected Products

• Mang Board WP plugin for WordPress — all versions through 1.8.6
• WordPress multi-site installations running Mang Board WP
• WordPress installations with the unfiltered_html capability disabled

Discovery Timeline

• 2025-04-24 - CVE-2025-3435 published to the National Vulnerability Database
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-3435

Vulnerability Analysis

The vulnerability is a Stored Cross-Site Scripting flaw in the Mang Board WP plugin. The plugin accepts user-supplied content in the board_header and board_footer configuration fields without applying sufficient sanitization on input or escaping on output. When board pages render, the injected markup is written directly into the HTML response and executed by the browser.

Exploitation requires an authenticated account with administrator privileges. The vulnerability is bounded to two specific scenarios: WordPress multi-site deployments, and single-site deployments where site owners have explicitly revoked the unfiltered_html capability from administrators. In default single-site WordPress installations, administrators are already permitted to post raw HTML, so the additional restriction does not apply.

Root Cause

The root cause is missing input validation and missing output encoding on the board_header and board_footer plugin settings. WordPress typically enforces content sanitization through functions such as wp_kses_post() or output escaping via esc_html() and esc_attr(). The plugin stored administrator-supplied values verbatim and rendered them without escaping, allowing <script> tags and event handlers to persist across page loads.

Attack Vector

An attacker who obtains administrator credentials, or who compromises an administrator account through phishing or credential reuse, navigates to the Mang Board configuration panel. The attacker submits a malicious payload in either the board_header or board_footer field. The payload persists in the database and executes whenever any user, including higher-privileged super-admins on multi-site networks, loads a board page. Because the attack requires an authenticated administrator and a specific configuration state, the practical exploitation scope is narrow.

No verified public proof-of-concept code is available for this vulnerability. Refer to the Wordfence Vulnerability Report for additional technical context.

Detection Methods for CVE-2025-3435

Indicators of Compromise

• Unexpected <script> tags, onerror=, or onload= attributes stored in the board_header or board_footer plugin option values in the wp_options table.
• Outbound requests from visitor browsers to unfamiliar third-party domains after loading Mang Board pages.
• Unauthorized administrator or super-admin sessions created shortly after board pages were viewed.

Detection Strategies

• Audit the wp_options table for Mang Board settings containing HTML tags, JavaScript event handlers, or URL-encoded script payloads.
• Review WordPress audit logs for changes to Mang Board plugin settings by administrator accounts.
• Deploy a web application firewall rule that inspects response bodies for script content originating from plugin-controlled regions of board pages.

Monitoring Recommendations

• Monitor administrator login activity on multi-site networks for anomalous source IPs or off-hours access.
• Alert on modifications to plugin configuration endpoints under /wp-admin/admin.php?page=mangboard*.
• Track browser Content Security Policy (CSP) violation reports to identify inline script execution attempts.

How to Mitigate CVE-2025-3435

Immediate Actions Required

• Update the Mang Board WP plugin to a version newer than 1.8.6 that includes the fix committed in WordPress Plugin Changeset 3272163.
• Audit all administrator accounts on multi-site WordPress networks and remove any that are unused or unrecognized.
• Inspect board_header and board_footer settings for any pre-existing malicious content and remove injected payloads.

Patch Information

The vendor addressed the vulnerability in the plugin trunk via changeset 3272163. Site operators should apply the patched release through the WordPress plugin update mechanism. Refer to the Wordfence Vulnerability Report for the specific fixed version.

Workarounds

• Restrict administrator access on multi-site networks using strong multi-factor authentication (MFA) to reduce the risk of account compromise.
• Deploy a Content Security Policy (CSP) header that disallows inline scripts from executing on board pages.
• Temporarily disable the Mang Board WP plugin on multi-site installations until the patch is applied.

# Configuration example: enforce a restrictive CSP via .htaccess
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'"