CVE-2026-2508: Gravity Forms Booking SQLi Vulnerability

CVE-2026-2508 Overview

CVE-2026-2508 is a time-based SQL injection vulnerability in the Gravity Forms Booking plugin for WordPress. The flaw affects all versions up to and including 2.7.1. The vulnerability stems from insufficient escaping of the staff_id parameter combined with inadequate preparation of the underlying SQL query. Authenticated attackers holding Subscriber-level access or above can append additional SQL statements to existing queries. Successful exploitation allows extraction of sensitive data from the WordPress database, including user credentials, session tokens, and booking records. The issue is tracked under CWE-89: SQL Injection.

Critical Impact
Authenticated Subscriber-level users can extract sensitive database contents through time-based blind SQL injection against the staff_id parameter.

Affected Products

Gravity Forms Booking plugin for WordPress, all versions through 2.7.1
WordPress sites with low-privilege user registration enabled
Booking workflows that accept the staff_id query parameter

Discovery Timeline

2026-06-25 - CVE-2026-2508 published to NVD
2026-06-25 - Last updated in NVD database

Technical Details for CVE-2026-2508

Vulnerability Analysis

The Gravity Forms Booking plugin processes the staff_id parameter without applying proper escaping or parameterized query binding. The plugin concatenates the user-supplied value directly into an SQL statement executed by the WordPress database layer. An authenticated attacker can inject SQL syntax that closes the original query context and appends arbitrary statements.

Because the application does not return query results directly to the attacker, exploitation relies on time-based blind techniques. The attacker injects conditional SLEEP() or BENCHMARK() payloads and infers data by measuring server response delays. This method extracts sensitive information one character at a time through Boolean evaluations.

The vulnerability requires authentication at the Subscriber tier, the lowest WordPress role. Sites permitting open registration expose this attack surface to any visitor who creates an account.

Root Cause

The root cause is the absence of prepared statements and input sanitization on the staff_id parameter. The plugin trusts client-supplied input and embeds it directly into SQL without using $wpdb->prepare() or equivalent placeholder binding. WordPress provides safe query APIs, but the affected code path bypasses them.

Attack Vector

The attack vector is network-based through HTTP requests sent to the plugin endpoints that accept staff_id. An authenticated attacker crafts a request containing a SQL payload such as a conditional time delay tied to a substring of a database value. Repeated requests reveal characters of administrator password hashes, secret keys, or other table contents. No user interaction is required beyond the attacker's own authenticated session.

The vulnerability mechanism is described in the Wordfence Vulnerability Report.

Detection Methods for CVE-2026-2508

Indicators of Compromise

HTTP requests containing the staff_id parameter with SQL keywords such as SLEEP, BENCHMARK, UNION, SELECT, or encoded variants
Unusually long response times from plugin endpoints handling booking queries
Repeated authenticated requests from a single Subscriber account targeting booking-related URLs
Database query logs showing malformed or concatenated statements referencing staff_id

Detection Strategies

Inspect web server access logs for staff_id values containing non-numeric characters, comment markers (--, #), or SQL functions
Enable WordPress query logging and review queries containing unexpected staff_id content
Deploy a Web Application Firewall rule that blocks SQL metacharacters in the staff_id parameter
Correlate Subscriber account activity with anomalous request volume against plugin endpoints

Monitoring Recommendations

Forward WordPress and web server logs to a centralized analytics platform for query inspection
Alert on response latency outliers from plugin endpoints, which signal time-based injection probing
Track newly registered Subscriber accounts that immediately interact with booking endpoints

How to Mitigate CVE-2026-2508

Immediate Actions Required

Update the Gravity Forms Booking plugin to a version newer than 2.7.1 once a fixed release is available from the vendor
Disable open user registration on WordPress sites that do not require it to reduce the authenticated attacker pool
Audit existing Subscriber accounts and remove unused or suspicious users
Rotate WordPress secret keys and administrator passwords if exploitation is suspected

Patch Information

Review the Gravity Booking Changelog for the patched version addressing CVE-2026-2508. Apply the update through the WordPress plugin manager or by replacing plugin files directly. Confirm the patch by verifying that staff_id is processed through $wpdb->prepare() or cast to an integer.

Workarounds

Deploy a Web Application Firewall rule blocking non-numeric staff_id values at the network edge
Temporarily deactivate the Gravity Forms Booking plugin until a vendor patch is installed
Restrict access to booking endpoints by IP allowlist where operationally feasible

bash

# WAF rule example: block non-numeric staff_id values
SecRule ARGS:staff_id "!@rx ^[0-9]+$" \
    "id:1002508,phase:2,deny,status:403,\
    msg:'CVE-2026-2508 staff_id SQLi attempt blocked'"