Atomic Edge analysis of CVE-2025-13854 (metadata-based):
This vulnerability is an authenticated Stored Cross-Site Scripting (XSS) flaw in the Curved Text WordPress plugin, version 0.1. The vulnerability exists within the ‘arctext’ shortcode handler, specifically in its handling of the ‘radius’ attribute. Attackers with Contributor-level access or higher can inject malicious scripts that execute in the context of any user viewing a page containing the compromised shortcode.
Atomic Edge research identifies the root cause as insufficient input sanitization and output escaping. The plugin likely accepts user-supplied input for the ‘radius’ shortcode attribute and directly echoes it into the page without proper neutralization. This inference is based on the CWE-79 classification and the vulnerability description. Without access to the patched version or source code diff, this conclusion is derived from the standard failure pattern for WordPress shortcode XSS vulnerabilities.
Exploitation requires an authenticated attacker with at least Contributor privileges. The attacker creates or edits a post or page, inserting the vulnerable shortcode with a malicious payload in the ‘radius’ attribute. The payload would be a JavaScript payload, such as `alert(‘XSS’)`, likely requiring HTML encoding or quotes to fit within the shortcode attribute context. The attack vector is the WordPress editor, not a direct HTTP endpoint, making WAF detection more challenging.
Remediation requires implementing proper output escaping. The plugin should use WordPress core escaping functions like `esc_attr()` when outputting the ‘radius’ attribute value within HTML. Input sanitization for shortcode attributes, using functions like `sanitize_text_field()`, is also a recommended defense-in-depth measure. A proper fix would validate the ‘radius’ value as a numeric parameter before use.
Successful exploitation leads to stored XSS. Injected scripts execute in the browser of any user who views the compromised page. This can result in session hijacking, administrative actions performed on behalf of the user, defacement, or malicious redirects. The CVSS vector indicates scope change (S:C), meaning the impact can propagate to other site components beyond the plugin itself.
Here you will find our ModSecurity compatible rule to protect against this particular CVE.
# Atomic Edge WAF Rule - CVE-2025-13854 (metadata-based)
# This rule targets POST requests to the WordPress post editor that contain the malicious 'arctext' shortcode.
# It inspects the POST body for the shortcode pattern with a script payload in the 'radius' attribute.
SecRule REQUEST_METHOD "@streq POST"
"id:10013854,phase:2,deny,status:403,chain,msg:'CVE-2025-13854: Curved Text Plugin Stored XSS via arctext shortcode',severity:'CRITICAL',tag:'CVE-2025-13854',tag:'WordPress',tag:'WAF',tag:'XSS'"
SecRule REQUEST_URI "@rx /wp-admin/(post.php|post-new.php)$" "chain"
SecRule REQUEST_BODY "@rx [arctext[^]]*radiuss*=s*['"][^'"]*<script"
"t:none,t:urlDecodeUni,t:htmlEntityDecode,t:lowercase"
// ==========================================================================
// Atomic Edge CVE Research | https://atomicedge.io
// Copyright (c) Atomic Edge. All rights reserved.
//
// LEGAL DISCLAIMER:
// This proof-of-concept is provided for authorized security testing and
// educational purposes only. Use of this code against systems without
// explicit written permission from the system owner is prohibited and may
// violate applicable laws including the Computer Fraud and Abuse Act (USA),
// Criminal Code s.342.1 (Canada), and the EU NIS2 Directive / national
// computer misuse statutes. This code is provided "AS IS" without warranty
// of any kind. Atomic Edge and its authors accept no liability for misuse,
// damages, or legal consequences arising from the use of this code. You are
// solely responsible for ensuring compliance with all applicable laws in
// your jurisdiction before use.
// ==========================================================================
// Atomic Edge CVE Research - Proof of Concept (metadata-based)
// CVE-2025-13854 - Curved Text <= 0.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes
<?php
/**
* This PoC simulates an authenticated Contributor user injecting a malicious shortcode into a post.
* It assumes valid WordPress credentials and the ability to create/edit posts.
* The exploit occurs via the standard WordPress post editor, not a direct plugin endpoint.
* Therefore, a direct HTTP PoC using cURL is not feasible without simulating the entire WordPress editor workflow (nonce, post ID, etc.).
* The attack is performed manually through the admin interface.
* A meaningful automated PoC would require full WordPress environment simulation.
*/
return null;
