CVE-2025-62939: Open Currency Converter XSS Vulnerability

CVE-2025-62939 Overview

CVE-2025-62939 is a stored cross-site scripting (XSS) vulnerability in the Open Currency Converter WordPress plugin (artiss-currency-converter) developed by Joe. The flaw affects all plugin versions up to and including 1.5.0. Attackers with low-privileged authenticated access can inject malicious JavaScript that persists in the application and executes in the browsers of users who view the affected pages. The issue is classified under CWE-79 for improper neutralization of input during web page generation. Successful exploitation can compromise session integrity, redirect users, or deface site content within the victim's browser context.

Critical Impact
Authenticated attackers can inject persistent JavaScript that executes against site visitors and administrators, enabling session theft and unauthorized actions within the WordPress environment.

Affected Products

Open Currency Converter WordPress plugin (artiss-currency-converter) versions up to and including 1.5.0
WordPress installations that expose the plugin's input handling to authenticated contributors or higher
Sites where administrators view content submitted through vulnerable plugin fields

Discovery Timeline

2025-10-27 - CVE-2025-62939 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in the NVD database

Technical Details for CVE-2025-62939

Vulnerability Analysis

The vulnerability stems from improper neutralization of user-supplied input rendered within web pages generated by the Open Currency Converter plugin. Input passed through the plugin is stored and later reflected in HTML output without sufficient encoding or sanitization. The attack requires user interaction and low privileges, but a successful payload persists and executes each time a user renders the affected view. Because the scope changes across a security boundary, injected script can affect users with higher privileges than the attacker. This category of flaw commonly enables administrative account takeover on multi-user WordPress sites.

Root Cause

The plugin fails to apply appropriate output escaping functions such as esc_html(), esc_attr(), or wp_kses() when rendering stored input. Data flows from persistent storage to the DOM without contextual encoding, allowing raw <script> payloads or event-handler attributes to execute. The artiss-currency-converter codebase does not enforce a sanitization pipeline on affected input fields through version 1.5.0.

Attack Vector

An authenticated attacker submits a crafted payload through the plugin's input handling. The payload is stored in the WordPress database and later served to any user who loads the affected page. When a targeted user, typically an administrator or site editor, opens the page, the browser executes the attacker's JavaScript in the context of the victim's session. See the Patchstack XSS Vulnerability Report for additional technical context.

No verified proof-of-concept code has been published. Payloads follow standard stored XSS patterns targeting unescaped WordPress plugin fields.

Detection Methods for CVE-2025-62939

Indicators of Compromise

Unexpected <script> tags, onerror attributes, or javascript: URIs stored in WordPress database tables associated with the plugin
Outbound HTTP requests from administrator browsers to unfamiliar domains after loading plugin-rendered pages
New or modified WordPress administrator accounts created shortly after plugin pages are viewed
Unexpected changes to WordPress options, themes, or plugin configurations

Detection Strategies

Inspect plugin-related database rows for HTML tags, script content, or encoded payloads that should not appear in currency conversion data
Review web server access logs for POST requests to plugin endpoints containing suspicious characters such as <, >, or javascript:
Monitor browser Content Security Policy (CSP) violation reports for inline script execution on pages that use the plugin

Monitoring Recommendations

Enable WordPress audit logging to record plugin configuration changes and content submissions by authenticated users
Alert on creation of new administrator accounts or modification of privileged user roles
Track anomalous session activity, including administrator sessions issuing REST API calls outside normal working patterns

How to Mitigate CVE-2025-62939

Immediate Actions Required

Restrict access to the Open Currency Converter plugin's input functionality until a patched version is deployed
Audit existing plugin content for stored payloads and remove any HTML or script tags from currency-related fields
Rotate WordPress administrator credentials and invalidate active sessions if suspicious content is found
Review authenticated user accounts and remove unnecessary contributor or higher privileges

Patch Information

A fixed release addressing CVE-2025-62939 has not been identified in the referenced advisory data. Monitor the Patchstack advisory and the plugin's WordPress.org page for a version above 1.5.0 that remediates the flaw. Apply the update through the WordPress admin dashboard once available.

Workarounds

Deactivate and remove the artiss-currency-converter plugin until a fixed version is published
Deploy a web application firewall (WAF) rule that blocks requests containing script tags or event-handler attributes targeting plugin endpoints
Enforce a strict Content Security Policy that disallows inline scripts and restricts script sources to trusted origins
Limit plugin-related capabilities to trusted administrator accounts only

bash

# Disable the vulnerable plugin via WP-CLI until a patch is released
wp plugin deactivate artiss-currency-converter
wp plugin delete artiss-currency-converter