CVE-2025-27289: Restrict Taxonomies Plugin XSS Vulnerability

CVE-2025-27289 Overview

CVE-2025-27289 is a reflected cross-site scripting (XSS) vulnerability in the Antoine Guillien Restrict Taxonomies plugin for WordPress. The flaw affects all versions of restrict-taxonomies from initial release through 1.3.3. The plugin fails to neutralize user-supplied input during web page generation, allowing attackers to inject malicious JavaScript that executes in a victim's browser. Exploitation requires a victim to click a crafted link, but no authentication is needed. The vulnerability is categorized under CWE-79 and can lead to session theft, credential harvesting, or actions performed on behalf of an authenticated administrator.

Critical Impact
A successful reflected XSS attack against a logged-in WordPress administrator can result in account takeover, plugin tampering, and the introduction of persistent backdoors into the site.

Affected Products

Antoine Guillien Restrict Taxonomies plugin for WordPress
All versions from n/a through 1.3.3
WordPress installations using the restrict-taxonomies plugin

Discovery Timeline

2025-04-17 - CVE-2025-27289 published to the National Vulnerability Database
2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-27289

Vulnerability Analysis

The vulnerability stems from improper neutralization of input during web page generation within the Restrict Taxonomies plugin. The plugin reflects attacker-controlled request parameters back into the HTML response without sufficient output encoding or input sanitization. When a victim loads a crafted URL, the malicious payload executes in the security context of the affected WordPress site.

Reflected XSS in administrative plugins is particularly impactful. WordPress administrators frequently interact with plugin settings pages, and JavaScript executed in that context inherits administrator privileges. Attackers can use this to create new admin users, modify content, or exfiltrate session cookies.

The attack vector is network-based and requires user interaction. A scope change occurs because injected script runs in the browser's same-origin context for the WordPress site, affecting resources beyond the initially vulnerable component.

Root Cause

The root cause is missing or insufficient output encoding when the plugin renders user-controlled parameters into HTML responses. Input passed via HTTP request parameters is included in the generated page without escaping characters such as <, >, ", and ', allowing an attacker to break out of HTML context and inject <script> tags or event handlers.

Attack Vector

An unauthenticated attacker crafts a URL containing a malicious JavaScript payload in a vulnerable parameter handled by the Restrict Taxonomies plugin. The attacker delivers the link through phishing, forum posts, or other social engineering. When an authenticated WordPress user, particularly an administrator, clicks the link, the payload reflects into the response and executes in their browser. The script can then issue authenticated requests to WordPress endpoints, harvest cookies, or redirect the user to attacker infrastructure.

No verified exploitation code is publicly available for CVE-2025-27289. Refer to the Patchstack Vulnerability Report for additional technical context.

Detection Methods for CVE-2025-27289

Indicators of Compromise

HTTP requests to restrict-taxonomies plugin endpoints containing URL-encoded <script>, onerror, onload, or javascript: tokens in query parameters
Outbound browser requests to unfamiliar domains originating from /wp-admin/ sessions
Unexpected creation of WordPress administrator accounts or modifications to plugin settings
Web server access logs showing repeated requests from a single source with varied payload encodings targeting the plugin

Detection Strategies

Inspect WordPress access logs for anomalous query strings on plugin pages, particularly long parameter values with HTML entities or script-like syntax
Deploy a web application firewall (WAF) with rules tuned to identify reflected XSS payloads against WordPress plugin paths
Correlate administrator session activity with subsequent unauthorized configuration changes through SIEM analytics

Monitoring Recommendations

Continuously monitor the wp-content/plugins/restrict-taxonomies/ directory for unauthorized file modifications
Alert on new administrator account creation events in the WordPress wp_users table
Capture and review Content Security Policy (CSP) violation reports for unexpected script sources

How to Mitigate CVE-2025-27289

Immediate Actions Required

Update the Restrict Taxonomies plugin to a version later than 1.3.3 once the vendor releases a fix
If no patched version is available, deactivate and remove the restrict-taxonomies plugin from affected WordPress installations
Force a password reset for all WordPress administrator accounts and invalidate active sessions
Audit recent administrative actions and plugin modifications for signs of exploitation

Patch Information

At the time of publication, the vulnerability affects all versions up to and including 1.3.3. Consult the Patchstack Vulnerability Report for the latest patch status and apply vendor updates as they become available.

Workarounds

Deploy a WAF with managed rulesets for WordPress that block reflected XSS payloads targeting plugin parameters
Implement a strict Content Security Policy that restricts inline scripts and limits permitted script sources
Restrict access to /wp-admin/ by IP allowlist where operationally feasible to reduce the attack surface
Train administrators to avoid clicking unverified links while authenticated to WordPress

bash

# Example: temporarily disable the vulnerable plugin via WP-CLI
wp plugin deactivate restrict-taxonomies
wp plugin delete restrict-taxonomies