CVE-2026-42381: FunnelKit SQLi Vulnerability Explained

CVE-2026-42381 Overview

CVE-2026-42381 is an unauthenticated SQL injection vulnerability in the Funnel Builder by FunnelKit WordPress plugin in versions up to and including 3.15.0.1. The flaw is classified under [CWE-89] Improper Neutralization of Special Elements used in an SQL Command. Attackers can send crafted requests over the network without authentication or user interaction, manipulating backend database queries against the WordPress site. The vulnerability carries a changed scope, allowing impact beyond the plugin's own data boundary. Patchstack published the advisory describing the issue affecting the funnel builder plugin used for sales funnel construction in WordPress storefronts.

Critical Impact
Unauthenticated attackers can inject arbitrary SQL into backend queries, exposing sensitive WordPress database contents including user credentials, session tokens, and order data.

Affected Products

Funnel Builder by FunnelKit plugin for WordPress
All versions up to and including 3.15.0.1
WordPress sites using FunnelKit for sales funnel and checkout workflows

Discovery Timeline

2026-06-15 - CVE-2026-42381 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2026-42381

Vulnerability Analysis

The vulnerability resides in the Funnel Builder by FunnelKit plugin, which provides sales funnel and checkout building functionality for WordPress and WooCommerce sites. The plugin accepts user-controlled input through one or more request parameters and incorporates that input into SQL statements without proper sanitization or parameterization. Because the affected endpoint does not require authentication, any remote attacker who can reach the WordPress site can supply malicious SQL fragments. The scope change indicator in the advisory suggests the injected query can read data outside the plugin's intended data context. Successful exploitation grants attackers the ability to enumerate the WordPress database, extract administrator password hashes, and potentially pivot to broader site compromise through credential theft.

Root Cause

The root cause is missing or insufficient input neutralization before the plugin passes user-supplied values into SQL queries. The plugin does not use prepared statements or the WordPress $wpdb->prepare() API consistently for the affected query paths, allowing attacker-controlled metacharacters to alter query semantics.

Attack Vector

An unauthenticated remote attacker sends a crafted HTTP request to a vulnerable plugin endpoint exposed by the WordPress site. The request includes SQL syntax embedded inside a parameter consumed by a vulnerable query. The database executes the modified statement and returns or acts on the injected logic. No privileges or user interaction are required, and the attack succeeds over the network against any reachable instance running an affected version.

No verified public proof-of-concept code is available in the references. See the Patchstack WordPress Vulnerability Report for advisory details.

Detection Methods for CVE-2026-42381

Indicators of Compromise

Unexpected outbound database query patterns containing UNION SELECT, SLEEP(, BENCHMARK(, or INFORMATION_SCHEMA references in WordPress request logs
HTTP requests to FunnelKit plugin endpoints (paths containing funnel-builder, funnelkit, or wfacp) with unusually long query strings or encoded SQL metacharacters
Spikes in 500-series errors or slow responses originating from /wp-admin/admin-ajax.php calls tied to FunnelKit actions
New or modified WordPress administrator accounts created without an audit trail

Detection Strategies

Inspect web server access logs for parameter values containing SQL keywords (SELECT, UNION, OR 1=1, --, 0x) targeting FunnelKit endpoints
Enable WordPress query logging or a database firewall to flag queries with suspicious comment sequences or stacked statements
Deploy a web application firewall ruleset that blocks SQL injection patterns on AJAX and REST routes registered by the plugin

Monitoring Recommendations

Monitor for repeated requests to the same FunnelKit endpoint from a single source IP, indicating injection probing or blind SQLi extraction
Alert on database accounts used by WordPress reading from tables outside the plugin's normal scope, such as wp_users or wp_usermeta
Correlate WAF SQLi alerts with subsequent administrator login events to identify successful credential theft

How to Mitigate CVE-2026-42381

Immediate Actions Required

Update the Funnel Builder by FunnelKit plugin to a version newer than 3.15.0.1 as soon as the vendor releases a patched build
Audit WordPress administrator accounts and rotate credentials for any account whose hash may have been exposed
Review WooCommerce order tables and customer records for unauthorized reads or modifications

Patch Information

Apply the patched version of Funnel Builder by FunnelKit referenced in the Patchstack WordPress Vulnerability Report. Versions at or below 3.15.0.1 remain vulnerable and should not be left in production.

Workarounds

Deactivate and remove the FunnelKit plugin until a fixed version can be installed if patching is not immediately possible
Restrict access to WordPress AJAX and REST endpoints with a web application firewall configured to block SQL injection signatures
Apply least-privilege principles to the WordPress database user, removing rights to access tables outside core plugin operation where feasible

bash

# Example WAF rule snippet to block SQLi patterns against FunnelKit endpoints
SecRule REQUEST_URI "@rx (funnel-builder|funnelkit|wfacp)" \
  "chain,deny,status:403,id:1004238,phase:2,msg:'Possible SQLi against FunnelKit'"
  SecRule ARGS "@rx (?i)(union(\s+all)?\s+select|sleep\s*\(|benchmark\s*\(|information_schema)" "t:none,t:urlDecodeUni"