EUVD-2026-46271
GHSA-q572-6pwx-4p26
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network-accessible unauthenticated nopriv AJAX endpoint (PR:N, AV:N); no code execution or data disclosure, only low-integrity content injection and availability degradation via spam.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
2DescriptionCVE.org
Ninja Forms WordPress plugin version 3.14.8 contains a client-side enforcement of server-side security vulnerability that allows unauthenticated attackers to bypass all form validation by merging attacker-controlled field metadata over server-loaded form definitions before validation runs. Attackers can craft a malicious AJAX submission overriding field types, removing required flags, and disabling CAPTCHA checks through the nopriv AJAX endpoint to trigger form actions such as email notifications and database storage with unverified, attacker-controlled content.
AnalysisAI
Validation bypass in Ninja Forms WordPress plugin 3.14.8 allows unauthenticated remote attackers to submit arbitrary content to any form by overriding server-side field definitions at the client layer before validation executes. By crafting a malicious AJAX payload targeting the WordPress nopriv (unauthenticated) AJAX endpoint, an attacker can strip required-field flags, override field types, and neutralize CAPTCHA protections - causing form actions such as email notifications and database writes to fire with fully attacker-controlled data. No public exploit code has been identified at time of analysis, and this vulnerability is not currently listed in the CISA KEV catalog, though the trivial attack complexity and zero-authentication requirement make opportunistic abuse straightforward.
Technical ContextAI
The vulnerability stems from CWE-602 (Client-Side Enforcement of Server-Side Security), a design flaw where security controls intended to be enforced on the server are instead reliant on client-supplied metadata. Ninja Forms (vendor: Saturday Drive, CPE: cpe:2.3:a:saturday_drive:ninja_forms:*:*:*:*:*:*:*:*) loads form definitions server-side but then merges attacker-supplied field metadata over those definitions prior to running validation. WordPress exposes a nopriv AJAX endpoint (wp-admin/admin-ajax.php) accessible without any authentication, which Ninja Forms uses for form submission handling. Because the merge of attacker-controlled field descriptors occurs before the validation pipeline runs, any field constraint - including required-field enforcement, field-type whitelisting, and CAPTCHA verification - can be stripped or overridden by the submitting party. This is a server-side trust failure masked as a client-side bypass: the server processes and acts upon metadata it should never have accepted as authoritative from the client.
RemediationAI
A patch is available from the vendor per the official Ninja Forms changelog at https://wordpress.org/plugins/ninja-forms/changelog/; administrators should upgrade to the latest version immediately. The exact patched version number is not confirmed in the available intelligence - verify against the changelog before deploying. As a compensating control while patching is pending, site operators can temporarily disable Ninja Forms entirely by deactivating the plugin via the WordPress admin dashboard, which eliminates the attack surface at the cost of losing all form functionality. If forms must remain active, consider restricting access to wp-admin/admin-ajax.php at the web server or WAF layer for non-authenticated users to specific known-good form IDs - though this requires careful tuning to avoid breaking legitimate submissions. Do not rely on client-side CAPTCHA or required-field UI controls as security mitigations, as this vulnerability specifically bypasses them.
More in Ninja Forms
View allThe Ninja Forms plugin before 2.9.42.1 for WordPress allows remote attackers to conduct PHP object injection attacks via
The AJAX action, wp_ajax_ninja_forms_sendwp_remote_install_handler, did not have a capability check on it, nor did it ha
The Ninja Forms plugin before 3.3.14.1 for WordPress allows CSV injection. Rated high severity (CVSS 8.6), this vulnerab
The Ninja Forms Contact Form WordPress plugin before 3.6.13 unserialises the content of an imported file, which could le
The Ninja Forms Contact Form WordPress plugin before 3.6.4 does not escape keys of the fields POST parameter, which coul
The Ninja Forms WordPress plugin is vulnerable to sensitive information disclosure via the bulk_export_submissions funct
The Ninja Forms WordPress plugin before 3.8.11 does not escape an URL before outputting it back in an attribute, leading
Unauth. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low at
The Ninja Forms Contact Form WordPress plugin before 3.6.22 does not properly escape user input before outputting it bac
In the Ninja Forms Contact Form WordPress plugin before 3.4.34, the wp_ajax_nf_oauth_connect AJAX action was vulnerable
An open redirect in the Ninja Forms plugin before 3.3.19.1 for WordPress allows Remote Attackers to redirect a user via
XSS in the Ninja Forms plugin before 3.3.18 for WordPress allows Remote Attackers to execute JavaScript via the includes
Same technique Authentication Bypass
View allShare
External POC / Exploit Code
Leaving vuln.today