CVE-2025-58783

Executive Summary

CVE-2025-58783 is a Missing Authorization vulnerability in the Gutentor WordPress plugin, affecting versions from n/a through 3.5.5. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized data access or manipulation. The vulnerability has a CVSS score of 4.3 (Medium), with an EPSS score of 0.0%, indicating low exploitation likelihood at this time. No public proof-of-concept (PoC) or exploit code has been identified, and no patch is currently available. As a WordPress plugin vulnerability, this issue is specific to the WordPress ecosystem and does not implicate Apache or Nginx.

Supply Chain & Package Security

This vulnerability affects the Gutentor WordPress plugin, which is distributed via the official WordPress plugin repository. Users are advised to monitor for updates and apply patches as soon as they become available. Since no patch exists, consider disabling the plugin or implementing additional access controls.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: Low
• Integrity Impact: None
• Availability Impact: None

The low CVSS score reflects the limited impact (only confidentiality), but the ease of exploitation (no authentication required) makes it a potential risk for information disclosure.

Deep Dive & Mechanics

The vulnerability stems from a Missing Authorization check in the Gutentor plugin. Specifically, certain AJAX actions or REST API endpoints do not properly verify user permissions before processing requests. This allows an unauthenticated attacker to trigger functions that should require at least a subscriber-level or higher role.

The affected functionality likely involves:

• Retrieving or modifying plugin settings.
• Accessing sensitive data such as user lists, post metadata, or configuration details.
• Triggering actions that could lead to further exploitation.

Since no patch exists, the exact vulnerable code path is not publicly confirmed, but the CWE-862 classification indicates a lack of capability checks in WordPress nonce verification or user capability validation.

Vulnerable vs. Patched Code

No patched version is available. The vulnerable code likely resembles:

// Vulnerable: No capability check
add_action('wp_ajax_nopriv_gutentor_action', 'gutentor_handle_action');
function gutentor_handle_action() {
    // Process request without checking user capabilities
    $data = $_POST['data'];
    // ... sensitive operation
}

A patched version would include:

// Patched: Capability check added
add_action('wp_ajax_gutentor_action', 'gutentor_handle_action');
function gutentor_handle_action() {
    if (!current_user_can('edit_posts')) {
        wp_die('Unauthorized');
    }
    $data = $_POST['data'];
    // ... sensitive operation
}

Exploitation & Lab Setup

Red Team

Since no public exploit exists, a red team would need to:

1. Identify vulnerable endpoints by analyzing the plugin's source code (version <= 3.5.5).
2. Craft HTTP requests to trigger unauthorized actions, e.g.:

   POST /wp-admin/admin-ajax.php HTTP/1.1
   Host: target-site.com
   Content-Type: application/x-www-form-urlencoded
   
   action=gutentor_action&data=malicious_payload
   

3. Monitor responses for sensitive data leakage.

Blue Team

To detect exploitation attempts:

• Monitor for unusual AJAX requests to admin-ajax.php with action parameters related to Gutentor.
• Look for requests from unauthenticated users to endpoints that should require authentication.
• Implement Web Application Firewall (WAF) rules to block known vulnerable patterns.

Indicators of Compromise (IOCs)

• Network: HTTP requests to /wp-admin/admin-ajax.php with action=gutentor_* from unauthenticated sources.
• Logs: WordPress debug logs showing unauthorized access attempts to Gutentor functions.
• File: Presence of unexpected Gutentor plugin files or modifications in wp-content/plugins/gutentor/.

Detection Engineering

YARA Rule

rule CVE_2025_58783_Gutentor_Missing_Auth {
    meta:
        description = "Detects Gutentor plugin files with missing authorization"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-58783"
    strings:
        $vuln_func = "wp_ajax_nopriv_gutentor" nocase
        $vuln_action = "gutentor_action" nocase
    condition:
        $vuln_func or $vuln_action
}

Sigma Rule

title: Gutentor Missing Authorization Exploitation Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects attempts to exploit CVE-2025-58783 in Gutentor plugin
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=gutentor_'
    condition: selection
falsepositives:
    - Legitimate Gutentor admin actions
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-58783 Gutentor Missing Authorization Attempt"; flow:to_server; content:"POST"; http_method; content:"admin-ajax.php"; http_uri; content:"action=gutentor_"; http_client_body; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Disable the Gutentor plugin until a patch is released.
2. Workaround: Implement a Web Application Firewall (WAF) rule to block unauthenticated requests to Gutentor AJAX endpoints.
3. Monitoring: Enable detailed logging for WordPress AJAX requests and review for anomalies.
4. Patch: Monitor the WordPress plugin repository for updates and apply as soon as available.
5. Alternative: Consider replacing Gutentor with a similar plugin that has active security support.

Valters IT
DevSecOps & Cyber Threat Intelligence