CVE-2026-24630: Stylish Cost Calculator XSS Vulnerability

CVE-2026-24630 Overview

CVE-2026-24630 is a Stored Cross-Site Scripting (XSS) vulnerability discovered in the Stylish Cost Calculator WordPress plugin developed by Design Stylish. The vulnerability arises from improper neutralization of user-supplied input during web page generation, allowing attackers to inject malicious scripts that persist in the application and execute in the browsers of other users who view the affected content.

Critical Impact
Authenticated attackers with low privileges can inject persistent malicious scripts into the WordPress site, potentially leading to session hijacking, credential theft, and unauthorized actions performed on behalf of legitimate users.

Affected Products

Stylish Cost Calculator WordPress Plugin versions up to and including 8.1.8
WordPress sites using vulnerable versions of the stylish-cost-calculator plugin

Discovery Timeline

2026-01-23 - CVE CVE-2026-24630 published to NVD
2026-01-26 - Last updated in NVD database

Technical Details for CVE-2026-24630

Vulnerability Analysis

This Stored XSS vulnerability (CWE-79) exists within the Stylish Cost Calculator WordPress plugin due to insufficient input sanitization and output encoding. The attack requires low privileges and user interaction, but operates across security boundaries, meaning malicious scripts can affect users with different privilege levels than the attacker. The vulnerability enables attackers to compromise the confidentiality, integrity, and availability of the affected system through persistent script injection.

Root Cause

The root cause of CVE-2026-24630 is the failure to properly neutralize user-controlled input before it is rendered in web pages. The Stylish Cost Calculator plugin does not adequately sanitize or escape data submitted through its input fields, allowing malicious JavaScript code to be stored in the database and subsequently rendered to other users without proper encoding. This violates secure coding principles that require all user input to be treated as untrusted and properly sanitized before storage or display.

Attack Vector

The attack is conducted over the network and requires an authenticated user with low-level privileges to exploit. The attacker submits malicious JavaScript payload through the plugin's input mechanisms, which gets stored in the WordPress database. When other users, including administrators, view content processed by the plugin, the malicious script executes in their browser context. This can lead to cookie theft, session hijacking, phishing attacks, or performing unauthorized actions with the victim's privileges. User interaction is required as victims must navigate to a page containing the injected payload.

The vulnerability allows cross-origin impact (changed scope), meaning an attacker operating within one security domain can affect resources in a different security domain. For additional technical details regarding the exploitation mechanism, refer to the Patchstack Security Advisory.

Detection Methods for CVE-2026-24630

Indicators of Compromise

Unexpected JavaScript code appearing in database fields associated with the Stylish Cost Calculator plugin
Unusual script tags or event handlers (e.g., onerror, onload, onclick) in plugin-generated content
Reports from users experiencing unexpected browser behavior or redirects when viewing calculator pages
Web application firewall logs showing XSS payload patterns targeting the plugin endpoints

Detection Strategies

Deploy web application firewall (WAF) rules to detect and block common XSS payload patterns in requests to WordPress
Implement Content Security Policy (CSP) headers to mitigate script execution from unauthorized sources
Use WordPress security plugins that scan for stored XSS vulnerabilities in plugin data
Regularly audit database content for suspicious script injections in plugin-related tables

Monitoring Recommendations

Monitor WordPress error logs and access logs for suspicious POST requests to plugin endpoints
Configure alerts for CSP violation reports which may indicate attempted XSS exploitation
Track changes to plugin configuration and data fields for unauthorized modifications
Implement real-time monitoring of user-submitted content for script injection patterns

How to Mitigate CVE-2026-24630

Immediate Actions Required

Update the Stylish Cost Calculator plugin to a patched version that addresses this vulnerability when available
Temporarily disable the Stylish Cost Calculator plugin if immediate patching is not possible
Audit existing calculator data for any previously injected malicious scripts
Implement Content Security Policy headers to reduce the impact of potential XSS attacks

Patch Information

Review the Patchstack Security Advisory for the latest patch information and updated plugin versions. Site administrators should update to a version higher than 8.1.8 once a security patch is released by the vendor.

Workarounds

Restrict access to the Stylish Cost Calculator plugin functionality to trusted administrators only until patched
Implement server-side input validation and output encoding as an additional security layer using a security plugin
Deploy a WAF with XSS protection rules to filter malicious payloads before they reach the application
Consider using an alternative cost calculator plugin that does not have known XSS vulnerabilities

To add Content Security Policy headers in WordPress, add the following to your theme's functions.php or use a security plugin:

php

// Add Content Security Policy headers to mitigate XSS impact
function add_security_headers() {
    header("Content-Security-Policy: script-src 'self' 'unsafe-inline' https://trusted-cdn.com; object-src 'none';");
    header("X-Content-Type-Options: nosniff");
    header("X-XSS-Protection: 1; mode=block");
}
add_action('send_headers', 'add_security_headers');