CVE-2025-31414: Cost Calculator Builder Stored XSS Vulnerability

CVE-2025-31414 Overview

CVE-2025-31414 is a stored Cross-Site Scripting (XSS) vulnerability [CWE-79] in the Stylemix Cost Calculator Builder plugin for WordPress. The flaw affects all plugin versions up to and including 3.2.65. An authenticated attacker with low privileges can inject persistent JavaScript payloads that execute in the browser of any user who loads the affected page. The scope-changed CVSS vector indicates the injected script can affect resources beyond the vulnerable component, including administrative sessions.

Critical Impact
Authenticated attackers can store malicious JavaScript that executes against site visitors and administrators, enabling session theft, forced administrative actions, and content defacement.

Affected Products

Stylemix Cost Calculator Builder for WordPress (cost-calculator-builder)
All versions from initial release through 3.2.65
WordPress sites running the plugin with contributor-level or higher user access

Discovery Timeline

2025-03-31 - CVE-2025-31414 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-31414

Vulnerability Analysis

The vulnerability stems from improper neutralization of user-supplied input during web page generation within the Cost Calculator Builder plugin. Input passed through the plugin's calculator configuration or field definitions is stored in the WordPress database and later rendered without adequate sanitization or output encoding. When the affected page loads, the browser interprets the stored payload as executable script rather than data.

The stored nature of the flaw distinguishes it from reflected XSS. The payload persists in the site database and executes for every visitor who reaches the injection point. Because the CVSS scope is marked as changed, the injected code can pivot into WordPress administrative contexts and interact with resources beyond the calculator component.

Root Cause

The root cause is missing or insufficient sanitization of input handled by the plugin before it is written to storage, combined with missing output encoding when the stored value is rendered in the calculator interface. WordPress provides helpers such as wp_kses_post, esc_attr, and esc_html for this purpose, but the vulnerable code path does not apply them consistently to attacker-controlled fields.

Attack Vector

Exploitation requires network access, low privileges, and user interaction. An attacker with access to the plugin's calculator configuration interface, typically a contributor, author, or editor role, injects a JavaScript payload into a vulnerable field. When an administrator or site visitor loads the page containing the calculator, the payload executes in their browser session. This can be used to steal authentication cookies, submit forged administrative requests, or deliver additional payloads. Full technical details are documented in the Patchstack XSS Vulnerability Advisory.

Detection Methods for CVE-2025-31414

Indicators of Compromise

Unexpected <script> tags, on* event handlers, or javascript: URIs stored in wp_postmeta or plugin-specific tables related to calculator configurations
Outbound requests from administrator browsers to unfamiliar domains shortly after loading pages containing the calculator shortcode
New or modified WordPress administrator accounts, plugin installations, or theme edits following visits to calculator pages
Anomalous authenticated sessions originating from IP addresses that do not match legitimate administrator activity

Detection Strategies

Inventory all WordPress installations and identify sites running cost-calculator-builder version 3.2.65 or earlier
Query plugin data stores for HTML tags, script fragments, or encoded payloads in fields that should contain plain text or numeric values
Review WordPress audit logs for calculator edits performed by low-privileged users prior to any suspicious administrative activity
Deploy content security policy (CSP) reporting to surface script executions from unexpected origins on pages containing the calculator

Monitoring Recommendations

Alert on modifications to Cost Calculator Builder configurations by non-administrator accounts
Monitor administrative sessions for cookie theft indicators such as concurrent logins from disparate geographies
Track outbound requests from WordPress hosts to newly registered or low-reputation domains

How to Mitigate CVE-2025-31414

Immediate Actions Required

Update Cost Calculator Builder to a version later than 3.2.65 as soon as a patched release is available from Stylemix
Audit user roles and revoke calculator editing privileges from accounts that do not require them
Review existing calculator configurations for injected HTML or JavaScript and remove any suspicious content
Rotate WordPress administrator credentials and invalidate active sessions if compromise is suspected

Patch Information

Refer to the Patchstack XSS Vulnerability Advisory for vendor patch status and the fixed release version. Apply the vendor-supplied update through the WordPress plugin manager or via WP-CLI.

Workarounds

Deactivate the Cost Calculator Builder plugin until a patched version is installed
Restrict access to plugin configuration pages using a Web Application Firewall (WAF) rule that blocks requests from non-administrator sessions
Enforce a strict Content Security Policy that disallows inline scripts on pages rendering calculator output

bash

# Update the plugin via WP-CLI once a patched version is released
wp plugin update cost-calculator-builder --version=<patched-version>

# Or deactivate the plugin as an interim workaround
wp plugin deactivate cost-calculator-builder