CVE-2026-19221 Overview
CVE-2026-19221 affects the Forminator Forms WordPress plugin in versions before 1.57.0.5. The plugin fails to restrict a network-wide setting to network administrators on multisite installations. Any single-site administrator can modify this setting and execute arbitrary code across the entire WordPress multisite network. The flaw is classified as improper control of code generation [CWE-94]. Exploitation requires an authenticated account with site administrator privileges on any subsite within the network.
Critical Impact
A compromised or malicious single-site administrator can pivot to full network-wide code execution, bypassing the trust boundary that separates subsite administrators from network administrators.
Affected Products
- Forminator Forms WordPress plugin versions before 1.57.0.5
- WordPress multisite installations running the vulnerable plugin
- Any subsite within a multisite network where the plugin is network-activated
Discovery Timeline
- 2026-08-22 - CVE-2026-19221 published to NVD
- 2026-08-26 - Last updated in NVD database
Technical Details for CVE-2026-19221
Vulnerability Analysis
The Forminator Forms plugin exposes a configuration option intended for network administrators in WordPress multisite deployments. The plugin does not verify that the requesting user holds the manage_network_options capability before accepting changes to this setting. A user with only site-level administrator rights on any subsite can therefore modify the network-wide setting.
Because the affected setting is consumed globally across the network, an attacker who alters it can inject content that leads to arbitrary code execution on every site in the network. This transforms a limited-scope subsite administrator into an attacker with effective control over the entire multisite installation.
The root weakness is code injection via a missing authorization check, mapped to [CWE-94]. WordPress multisite explicitly separates subsite administrators from network (super) administrators, and plugins are expected to enforce that boundary for any network-scoped configuration.
Root Cause
The plugin's request handler for the affected setting checks only that the caller is an administrator, not that the caller is a network administrator. It also does not sanitize the input in a way that prevents code from being executed when the value is later processed.
Attack Vector
An authenticated attacker who has obtained or been granted administrator rights on any single site in the multisite network submits a crafted request to the plugin's network setting endpoint. The plugin accepts the change without verifying network-level authorization. When the setting is subsequently processed on any site in the network, the attacker-controlled payload is executed in the WordPress PHP context, resulting in full compromise of the network.
See the WPScan Vulnerability Report for additional technical detail.
Detection Methods for CVE-2026-19221
Indicators of Compromise
- Modifications to Forminator Forms network-level settings originating from a non-super-admin account
- Unexpected PHP files, cron entries, or scheduled tasks created under wp-content/ after Forminator setting changes
- Outbound network connections from the WordPress host to unfamiliar hosts following administrative activity on the plugin
Detection Strategies
- Audit WordPress wp_options and wp_sitemeta entries related to Forminator for changes made by users lacking the manage_network capability
- Review web server access logs for POST requests to Forminator administrative endpoints from subsite administrators
- Monitor plugin update status across the multisite network and flag installations still running versions before 1.57.0.5
Monitoring Recommendations
- Alert on any process spawned by the PHP-FPM or web server user that executes shells, package managers, or reconnaissance binaries
- Track user role assignments and privilege changes across all subsites to detect attacker persistence
- Correlate WordPress audit logs with EDR telemetry on the underlying host to link plugin activity to process execution
How to Mitigate CVE-2026-19221
Immediate Actions Required
- Upgrade Forminator Forms to version 1.57.0.5 or later on every site in the multisite network
- Review the list of subsite administrators and remove accounts that no longer require access
- Inspect Forminator network-wide settings for unexpected values and revert any unauthorized changes
Patch Information
The vendor fixed the issue in Forminator Forms 1.57.0.5 by restricting the affected setting to users with network administrator privileges. Refer to the WPScan Vulnerability Report for advisory details and version references.
Workarounds
- Network-deactivate Forminator Forms until every site can be updated to the patched version
- Restrict subsite administrator accounts to trusted personnel only, given that the attack requires that role
- Place the WordPress admin interface behind an IP allowlist or authentication proxy to reduce exposure of administrative endpoints
# Update Forminator Forms across a WordPress multisite using WP-CLI
wp plugin update forminator --network --version=1.57.0.5
wp plugin list --name=forminator --fields=name,status,version --network
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
