CVE-2026-80437 Overview
CVE-2026-80437 is a shortcode injection vulnerability in the Ninja Forms plugin for WordPress, affecting versions from 3.14.10 before 3.15.2. The plugin fails to prevent shortcodes contained in request-derived values from being executed when substituted into content later processed for shortcodes. Unauthenticated attackers can trigger execution of any shortcode registered on the target site. The flaw is tracked under CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component).
Critical Impact
Unauthenticated attackers can execute arbitrary registered shortcodes, enabling access to data or functionality exposed by any installed shortcode-providing plugin.
Affected Products
- Ninja Forms WordPress plugin versions 3.14.10 through 3.15.1
- WordPress installations with Ninja Forms enabled
- Sites with additional plugins exposing sensitive shortcodes
Discovery Timeline
- 2026-09-06 - CVE-2026-80437 published to NVD
- 2026-09-08 - Last updated in NVD database
Technical Details for CVE-2026-80437
Vulnerability Analysis
The Ninja Forms plugin accepts request-derived values and substitutes them into content that the plugin later passes through WordPress shortcode processing. Because the substitution occurs before the shortcode parser runs, any shortcode markup embedded in attacker-supplied input becomes eligible for execution. This transforms untrusted request data into executable directives inside the WordPress rendering pipeline.
Exploitation requires no authentication and no user interaction, though the CVSS vector indicates high attack complexity. The impact scope depends on which shortcodes the target site has registered through Ninja Forms itself, WordPress core, and any third-party plugins.
Root Cause
The root cause is improper neutralization of shortcode syntax in user-controlled input before it reaches the do_shortcode() processing stage. The plugin treats request values as inert data during substitution but then submits the resulting composite string to a shortcode parser that interprets [shortcode] tokens. This confusion between data and code corresponds to the CWE-74 injection class.
Attack Vector
An attacker crafts an HTTP request to a Ninja Forms endpoint that accepts values later interpolated into shortcode-processed content. The attacker embeds shortcode markup, such as tags exposed by other installed plugins, within those request values. When Ninja Forms processes the content, WordPress executes the injected shortcodes with the plugin's execution context. The consequences depend entirely on the capabilities of shortcodes registered on the target instance, ranging from information disclosure to state changes exposed through shortcode handlers.
Refer to the WPScan Vulnerability Report for additional technical details.
Detection Methods for CVE-2026-80437
Indicators of Compromise
- HTTP requests to Ninja Forms endpoints containing bracketed shortcode syntax such as [ and ] in form field values
- Unexpected shortcode output rendered in form submission responses or downstream email or storage sinks
- Requests to admin-ajax.php or REST routes with action parameters referencing Ninja Forms handlers combined with shortcode-like payloads
Detection Strategies
- Inspect web server and WordPress logs for POST bodies to Ninja Forms endpoints containing shortcode delimiters in fields that should be plain text
- Enable Ninja Forms submission logging and review stored submissions for shortcode markup embedded in name, email, or message fields
- Correlate anomalous form submissions with subsequent execution of shortcodes registered by other plugins, especially those returning sensitive data
Monitoring Recommendations
- Deploy a web application firewall rule that flags shortcode delimiters in Ninja Forms request parameters
- Alert on installed plugins that register shortcodes returning user data, secrets, or administrative content
- Monitor plugin version inventory to identify WordPress sites still running Ninja Forms below 3.15.2
How to Mitigate CVE-2026-80437
Immediate Actions Required
- Upgrade Ninja Forms to version 3.15.2 or later on all WordPress installations
- Audit installed plugins for shortcodes that expose sensitive information or privileged actions
- Review recent form submissions for shortcode syntax indicating attempted exploitation
Patch Information
The vendor addressed CVE-2026-80437 in Ninja Forms version 3.15.2. The fix prevents shortcodes in request-derived values from being executed during subsequent shortcode processing. Consult the WPScan Vulnerability Report for advisory details and patched-version guidance.
Workarounds
- Restrict access to Ninja Forms submission endpoints using a web application firewall rule that strips or blocks shortcode delimiters in field values
- Temporarily disable the Ninja Forms plugin on high-value sites until the patched version is deployed
- Deregister non-essential shortcodes that expose sensitive data using remove_shortcode() in a mu-plugin until patching completes
# Update Ninja Forms via WP-CLI on affected hosts
wp plugin update ninja-forms --version=3.15.2
wp plugin get ninja-forms --field=version
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
