CVE-2025-57941: Append Link on Copy Stored XSS Vulnerability

CVE-2025-57941 Overview

CVE-2025-57941 is a stored Cross-Site Scripting (XSS) vulnerability in the JonathanMH Append Link on Copy WordPress plugin. The flaw affects all versions of the plugin from initial release through version 0.2. It stems from improper neutralization of input during web page generation, classified under [CWE-79]. An authenticated attacker with high privileges can inject persistent JavaScript payloads that execute in the browsers of users who view affected pages. The issue was published to the National Vulnerability Database (NVD) on 2025-09-22 through a Patchstack advisory.

Critical Impact
Stored XSS in the append-link-on-copy plugin enables persistent JavaScript execution in visitor browsers, with a scope change that can impact resources beyond the vulnerable component.

Affected Products

JonathanMH Append Link on Copy WordPress plugin
All versions up to and including 0.2
WordPress sites with the append-link-on-copy plugin installed and active

Discovery Timeline

2025-09-22 - CVE-2025-57941 published to NVD via Patchstack advisory
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-57941

Vulnerability Analysis

The vulnerability is a stored Cross-Site Scripting flaw in the Append Link on Copy plugin for WordPress. The plugin fails to properly sanitize and encode user-controlled input before rendering it in generated web pages. An attacker with high-privilege access can save malicious HTML or JavaScript payloads through plugin-controlled inputs. These payloads persist in the site database and execute when other users load the affected content.

Exploitation requires user interaction, meaning a target must load or interact with the injected content for the payload to fire. The scope is changed, which means the injected script can affect resources outside the security boundary of the vulnerable component. Successful exploitation impacts confidentiality, integrity, and availability at a limited level.

Root Cause

The root cause is the absence of output encoding and input sanitization in the plugin's page-generation logic. Data supplied through plugin settings or content fields is written into the DOM without escaping HTML control characters such as <, >, and quotation marks. This allows attacker-supplied markup to be interpreted as executable script rather than inert text.

Attack Vector

An attacker with administrative or equivalent high-privilege access to the WordPress admin interface stores a JavaScript payload through a plugin field that is later rendered on the front end or in the admin dashboard. When another authenticated user or site visitor loads the affected page, the browser executes the payload in the site's origin context. This enables session token theft, forced administrative actions, defacement, or redirection to attacker infrastructure. See the Patchstack advisory for additional technical detail.

Detection Methods for CVE-2025-57941

Indicators of Compromise

Unexpected <script> tags, event handlers such as onerror or onload, or javascript: URIs present in plugin-controlled fields stored in the wp_options or wp_postmeta tables.
Outbound HTTP requests from visitor browsers to unfamiliar domains when loading pages that render append-link-on-copy content.
Admin user sessions performing actions inconsistent with the account owner's activity patterns.

Detection Strategies

Audit WordPress database tables for plugin-stored values containing HTML or script markup that should be plain text.
Deploy a Web Application Firewall (WAF) rule set that flags stored XSS patterns in WordPress plugin admin endpoints.
Monitor browser Content Security Policy (CSP) violation reports for inline script execution originating from plugin-rendered pages.

Monitoring Recommendations

Enable WordPress audit logging to capture plugin setting changes and identify the source account for any malicious modification.
Track authenticated admin activity for anomalous option updates targeting the append-link-on-copy plugin.
Alert on new administrator account creation or role escalation events following plugin configuration changes.

How to Mitigate CVE-2025-57941

Immediate Actions Required

Deactivate and remove the Append Link on Copy plugin from all WordPress sites until a patched release is available.
Review all administrator and editor accounts and rotate credentials for any account that may have been used to inject content.
Inspect plugin settings and rendered pages for existing script payloads and remove any unauthorized content.

Patch Information

No fixed version is listed in the advisory. The vulnerability affects the plugin from initial release through version 0.2, and the Patchstack advisory does not identify a patched release. Site administrators should monitor the Patchstack advisory for update notifications.

Workarounds

Uninstall the plugin entirely if it is not business-critical, since no vendor patch is currently available.
Restrict WordPress administrator privileges to a minimal set of trusted accounts and enforce multi-factor authentication.
Deploy a WAF policy that blocks HTML and script metacharacters in requests to plugin administrative endpoints.

bash

# Configuration example: remove the vulnerable plugin via WP-CLI
wp plugin deactivate append-link-on-copy
wp plugin delete append-link-on-copy

# Verify removal
wp plugin list | grep append-link-on-copy