CVE-2025-26761

Executive Summary

CVE-2025-26761 is a DOM-Based Cross-Site Scripting (XSS) vulnerability in the WordPress plugin Easy Elementor Addons by Hashthemes, affecting versions up to and including 2.1.5. This flaw allows an unauthenticated attacker to inject malicious scripts into the DOM of a victim's browser, bypassing server-side sanitization. The vulnerability is triggered when user-supplied input is improperly neutralized during web page generation, leading to script execution in the context of the victim's session. Given the plugin's popularity in the WordPress ecosystem, this poses a significant risk to site administrators and visitors.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. No supply chain compromise has been identified, but the lack of a patch from the vendor increases the risk of malicious actors embedding exploits in third-party distributions or forked versions.

CVSS Breakdown & Threat Level

• CVSS Score: 6.5 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must click a crafted link or visit a malicious page)
• Scope: Changed (impact on other components)
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: Low

Threat Level: Medium. Exploitation requires user interaction, but the DOM-based nature allows for stealthy attacks that bypass traditional WAF filters.

Deep Dive & Mechanics

The vulnerability exists in the easy-elementor-addons plugin's JavaScript handling of user-controlled input. Specifically, the plugin fails to sanitize data passed to DOM manipulation functions (e.g., innerHTML, document.write, or jQuery's .html()). An attacker can craft a URL with a malicious payload in a query parameter or fragment identifier that is then reflected into the DOM without proper encoding.

Root Cause: The plugin uses window.location.hash or URLSearchParams to read input and directly injects it into the page via JavaScript, without escaping HTML entities or using safe DOM APIs like textContent.

Attack Flow:

1. Attacker crafts a URL: https://victim-site.com/?elementor-addon=#<img src=x onerror=alert(1)>
2. Victim clicks the link.
3. The plugin's JavaScript reads the fragment and inserts it into the DOM.
4. The browser executes the injected script.

Vulnerable vs. Patched Code

Vulnerable Code (JavaScript snippet):

var hash = window.location.hash.substring(1);
document.getElementById('my-addon').innerHTML = hash;

Patched Code (hypothetical fix):

var hash = window.location.hash.substring(1);
var safeElement = document.createTextNode(hash);
document.getElementById('my-addon').appendChild(safeElement);

The vulnerable code directly assigns user input to innerHTML, while the patched version uses createTextNode to safely encode the input.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• A WordPress site with Easy Elementor Addons <= 2.1.5 installed and active.
• A victim user with a modern browser.

Exploit Steps:

1. Identify a page that uses the vulnerable plugin (e.g., a page with an Elementor addon widget).
2. Craft a malicious URL with a DOM-based XSS payload:

   https://victim-site.com/?page_id=123#<img src=x onerror=alert(document.cookie)>
   

3. Send the link to the victim via phishing email or social engineering.
4. Upon clicking, the payload executes in the victim's browser, exfiltrating cookies or performing actions on their behalf.

No public exploit code is available for this CVE.

Blue Team (Detection & Defense)

Detection:

• Monitor web server logs for requests containing suspicious fragment identifiers (e.g., #<script, #<img, #<svg).
• Use browser-based CSP headers to block inline scripts.

Defense:

• Disable or remove the vulnerable plugin until a patch is released.
• Implement a Web Application Firewall (WAF) rule to block DOM-based XSS patterns in URL fragments.
• Educate users to avoid clicking suspicious links.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests containing #<script or #<img in the URL fragment.
  • Outbound connections to attacker-controlled domains from the victim's browser.
• File IOCs:
  • Modified JavaScript files in /wp-content/plugins/easy-elementor-addons/ (if attacker gains write access).
• Behavioral IOCs:
  • Unexpected DOM modifications in pages using the plugin.
  • Unusual JavaScript execution in the browser console.

Detection Engineering

YARA Rule

rule CVE_2025_26761_DOM_XSS {
    meta:
        description = "Detects DOM-based XSS in Easy Elementor Addons plugin"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "CVE-2025-26761"
    strings:
        $s1 = "window.location.hash" ascii wide nocase
        $s2 = "innerHTML" ascii wide nocase
        $s3 = "easy-elementor-addons" ascii wide nocase
    condition:
        all of them
}

Sigma Rule

title: CVE-2025-26761 DOM-Based XSS in Easy Elementor Addons
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects potential exploitation of DOM-based XSS in Easy Elementor Addons plugin
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains: '#<'
    condition: selection
falsepositives:
    - Legitimate use of hash fragments with '<' character (rare)
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-26761 DOM-Based XSS Attempt"; flow:to_server; content:"#<"; http_uri; pcre:"/#<(script|img|svg|iframe)/i"; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released by the vendor.
2. Implement a Content Security Policy (CSP) that blocks inline scripts and restricts script sources.
3. Use a Web Application Firewall (WAF) with rules to block DOM-based XSS payloads in URL fragments.

Long-Term Fix:

• The vendor must release a patched version that properly sanitizes user input before DOM insertion.
• Developers should use safe DOM APIs (e.g., textContent, setAttribute) and avoid innerHTML with untrusted data.

Workaround:

• If the plugin cannot be disabled, modify the JavaScript file to replace innerHTML with textContent (requires code access).

Valters IT
Securing Digital Frontiers