CVE-2026-92403 Overview
CVE-2026-92403 affects the Secure Custom Fields WordPress plugin in versions before 6.9.4. The plugin fails to verify that a front-end form submission corresponds to the form originally rendered to the visitor. Unauthenticated users can submit against a different registered form and modify the title and content of the post bound to that form. The flaw is categorized under CWE-863: Incorrect Authorization.
Critical Impact
Unauthenticated attackers can tamper with WordPress post titles and content on affected sites by cross-submitting to registered Secure Custom Fields forms.
Affected Products
- Secure Custom Fields WordPress plugin versions prior to 6.9.4
- WordPress sites exposing Secure Custom Fields front-end forms
- Sites where multiple Secure Custom Fields forms are registered and bound to posts
Discovery Timeline
- 2026-09-19 - CVE-2026-92403 published to the National Vulnerability Database
- 2026-09-21 - Last updated in NVD database
Technical Details for CVE-2026-92403
Vulnerability Analysis
The Secure Custom Fields plugin renders front-end forms that let visitors submit data bound to specific WordPress posts. When a submission arrives, the plugin does not confirm that the posted form identifier matches the form the visitor was originally served. An attacker can craft a request that references a different registered form and route the submission to a post the attacker never intended to interact with legitimately.
Because the check is missing, the submission handler accepts the attacker-controlled form reference and applies the associated update logic. This lets an unauthenticated user modify the title and content of the bound post. The impact is limited to integrity of post fields exposed through registered forms; there is no direct code execution or credential disclosure per the advisory.
The WPScan Vulnerability Report documents the issue and the fixed version.
Root Cause
The root cause is a broken authorization check in the form submission handler [CWE-863]. The handler trusts the submitted form identifier without validating that it matches the form rendered in the visitor's session or that the visitor is authorized to update the bound post. This design flaw allows form-context substitution during submission processing.
Attack Vector
Exploitation is network-based and requires no authentication or user interaction. An attacker locates a public page that renders any Secure Custom Fields front-end form, then issues a crafted POST request referencing a different registered form identifier bound to a target post. The plugin processes the submission and updates the target post's title and content. Attack complexity is high because the attacker must enumerate valid form identifiers and target post bindings.
No verified public exploit code is available. See the WPScan Vulnerability Report for additional technical details.
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Stop Identity AttacksDetection Methods for CVE-2026-92403
Indicators of Compromise
- Unexpected changes to WordPress post titles or content on posts bound to Secure Custom Fields forms
- POST requests to Secure Custom Fields submission endpoints referencing form IDs not present on the requested page
- Repeated submissions from a single client cycling through different form identifiers
- WordPress revision history entries authored by anonymous or unexpected sessions
Detection Strategies
- Compare submitted form identifiers in web server logs against the form rendered on the referring URL
- Alert on Secure Custom Fields submission endpoints receiving traffic without a matching page render event in the same session
- Monitor the wp_posts and wp_post_revisions tables for high-frequency title or content updates on posts bound to front-end forms
Monitoring Recommendations
- Enable WordPress audit logging for post updates including source IP and user context
- Forward web access logs and WordPress audit events to a centralized analytics platform for correlation
- Baseline normal submission volume per form and alert on statistical deviations
How to Mitigate CVE-2026-92403
Immediate Actions Required
- Upgrade the Secure Custom Fields plugin to version 6.9.4 or later on all WordPress installations
- Audit posts bound to Secure Custom Fields front-end forms for unauthorized title or content changes
- Restore modified posts from backups or WordPress revision history where tampering is confirmed
Patch Information
The vendor addressed the issue in Secure Custom Fields version 6.9.4 by validating that the submitted form corresponds to the form originally rendered. Administrators should update through the WordPress plugin management interface or WP-CLI. Refer to the WPScan Vulnerability Report for the fixed version reference.
Workarounds
- Temporarily disable Secure Custom Fields front-end forms until the plugin is updated
- Restrict access to pages hosting Secure Custom Fields forms using authentication or IP allowlists
- Deploy a web application firewall rule that rejects submissions where the referenced form ID does not match the referrer page
# Update Secure Custom Fields using WP-CLI
wp plugin update secure-custom-fields --version=6.9.4
wp plugin list --name=secure-custom-fields --fields=name,status,version
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
