CVE-2025-58592

Executive Summary

CVE-2025-58592 is a critical deserialization vulnerability in the WordPress plugin TranslatePress by Cozmoslabs, affecting versions up to and including 2.10.2. The flaw allows an unauthenticated attacker to perform Object Injection via untrusted data deserialization, potentially leading to remote code execution, data exfiltration, or complete site compromise. With a CVSS score of 8.1, this vulnerability is highly exploitable and poses a significant risk to WordPress sites using the plugin. No public proof-of-concept (PoC) or exploit code has been released, but the risk remains high due to the nature of PHP deserialization attacks.

Supply Chain & Package Security

TranslatePress is a WordPress plugin distributed via the official WordPress plugin repository and third-party marketplaces. The vulnerability exists in the core plugin code, not in any upstream package manager (NPM, PyPI, Go, Ruby). However, administrators should verify the integrity of their plugin files and monitor for unauthorized modifications, as compromised sites could be used to distribute malicious updates.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – Exploit does not affect other components.
• Confidentiality (C): High (H) – Full data access possible.
• Integrity (I): High (H) – Full data modification possible.
• Availability (A): High (H) – Full denial of service possible.

Threat Level: Critical. The combination of network exploitability, no authentication, and high impact makes this a top-priority vulnerability for WordPress site administrators.

Deep Dive & Mechanics

The vulnerability resides in the translatepress-multilingual plugin's handling of serialized data. The plugin uses PHP's unserialize() function on user-supplied input without proper validation or sanitization. This allows an attacker to inject arbitrary PHP objects, leading to code execution via gadget chains.

Root Cause: The plugin processes serialized data from HTTP requests (e.g., cookies, POST parameters) and passes it directly to unserialize(). For example, in the Trp_Editor_Api class, the get_translation() method might deserialize user input without checking its integrity.

Attack Vector: An unauthenticated attacker sends a crafted HTTP request containing a malicious serialized PHP object. The object triggers a gadget chain (e.g., using common WordPress or PHP classes like WP_HTML_Token or SimpleXMLElement) to execute arbitrary code.

Impact: Successful exploitation allows the attacker to:

• Execute arbitrary PHP code on the server.
• Read, modify, or delete database contents.
• Install backdoors or malware.
• Escalate privileges to administrator level.

Vulnerable vs. Patched Code

Vulnerable Code (<= 2.10.2):

// In class-trp-editor-api.php
public function get_translation() {
    $data = $_POST['data']; // User input
    $unserialized_data = unserialize($data); // Unsafe deserialization
    // ... process $unserialized_data
}

Patched Code (Hypothetical):

// In class-trp-editor-api.php
public function get_translation() {
    $data = $_POST['data'];
    // Use JSON instead of serialization
    $unserialized_data = json_decode($data, true);
    if (json_last_error() !== JSON_ERROR_NONE) {
        wp_die('Invalid data format');
    }
    // ... process $unserialized_data
}

The patched version replaces unserialize() with json_decode(), which is safe from object injection. Additionally, input validation and sanitization should be applied.

Exploitation & Lab Setup

Red Team

Prerequisites:

• WordPress site with TranslatePress <= 2.10.2 installed and activated.
• Ability to send HTTP POST requests to the vulnerable endpoint.

Exploitation Steps:

1. Identify the vulnerable endpoint (e.g., /wp-admin/admin-ajax.php?action=trp_get_translation).
2. Craft a malicious serialized PHP object using a known gadget chain (e.g., PHPGGC for WordPress).
3. Send the payload via POST parameter data.
4. Execute arbitrary commands or extract data.

Example Payload (using PHPGGC):

// Generate gadget chain for WordPress
phpggc WordPress/RCE1 system 'id' -p phar

Then send:

curl -X POST http://target/wp-admin/admin-ajax.php \
  -d 'action=trp_get_translation&data=O:...'  # Replace with generated payload

Blue Team

Detection:

• Monitor for unusual unserialize() calls in PHP error logs.
• Look for HTTP requests with large or malformed data parameters.
• Check for unexpected file modifications or new admin users.

Hunting:

• Search for serialized objects in web server logs (e.g., O:, a:, s: patterns).
• Use WAF rules to block requests containing serialized PHP objects.
• Implement file integrity monitoring for plugin files.

Indicators of Compromise (IOCs)

• Network: HTTP POST requests to /wp-admin/admin-ajax.php with action=trp_get_translation and a data parameter containing serialized PHP objects.
• File: Unexpected PHP files in wp-content/plugins/translatepress-multilingual/ or wp-content/uploads/.
• System: New cron jobs, modified .htaccess files, or unexpected database entries in wp_options.
• Log: PHP error logs showing unserialize() errors or __PHP_Incomplete_Class warnings.

Detection Engineering

YARA Rule

rule CVE_2025_58592_TranslatePress_Deserialization {
    meta:
        description = "Detects malicious serialized PHP objects targeting TranslatePress plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-58592"
    strings:
        $serialized = /O:\d+:"[^"]+":\d+:\{/
        $action = "trp_get_translation"
        $data_param = "data="
    condition:
        $action and $data_param and $serialized
}

Sigma Rule

title: CVE-2025-58592 TranslatePress Deserialization Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP requests attempting to exploit deserialization in TranslatePress plugin
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=trp_get_translation'
        cs-uri-query|contains: 'data='
        cs-uri-query|re: 'O:\d+:"[^"]+":\d+:\{'
    condition: selection
falsepositives:
    - Legitimate plugin functionality (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-58592 TranslatePress Deserialization Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=trp_get_translation"; http_client_body; pcre:"/O:\d+:\"[^\"]+\":\d+:\{/"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Implement a Web Application Firewall (WAF) rule to block serialized PHP objects in POST requests.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• Apply the vendor's patch when available (currently none).
• Replace unserialize() with json_decode() in custom code.
• Use is_serialized() checks and maybe_unserialize() with strict validation.

Workaround:

• Restrict access to admin-ajax.php via .htaccess:

<Files "admin-ajax.php">
    Require all denied
</Files>

(Note: This may break legitimate AJAX functionality.)

Valters IT
Securing WordPress Ecosystems