CVE-2026-85122 in Easy Form Builder Plugin
Summary
by MITRE • 09/18/2026
The Easy Form Builder by WhiteStudio WordPress plugin before 4.2.0 does not validate a submitted value against the stored configuration for some of its form types, allowing unauthenticated users to store arbitrary content which is then rendered unescaped in an admin page, leading to Stored XSS.
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Analysis
by VulDB Data Team • 09/18/2026
The vulnerability identified in Easy Form Builder by WhiteStudio prior to version 4.2.0 represents a critical security flaw rooted in insufficient input validation and improper output encoding within the WordPress plugin architecture. This issue specifically affects certain form types where the application fails to verify that user-supplied data aligns with expected configuration parameters before persisting it to the database. By bypassing these validation checks, an unauthenticated attacker can inject malicious scripts into the system's storage layer. The severity of this vulnerability is compounded by the fact that the stored content is subsequently rendered without proper escaping on administrative pages, transforming a simple input flaw into a persistent and high-impact attack vector known as Stored Cross-Site Scripting or XSS.
From a technical perspective, the core deficiency lies in the lack of strict type checking and sanitization routines for specific form submission fields. When a user submits data through these vulnerable forms, the plugin accepts the payload without confirming that it conforms to predefined structural constraints defined in its configuration settings. This oversight allows attackers to craft payloads containing JavaScript code or other executable content which is then saved directly into the WordPress database. Because the application trusts this stored data implicitly during subsequent administrative operations, the malicious script becomes part of the page source when an administrator views the form submissions or related management interfaces.
The operational impact of this vulnerability is severe due to its unauthenticated nature and persistent storage characteristics. Since no authentication is required to exploit the initial injection point, any internet user can trigger the flaw without needing valid credentials for the WordPress site. Once the malicious script is stored, it executes in the context of every administrator who accesses the affected page. This allows attackers to hijack administrative sessions by stealing cookies or session tokens, perform actions on behalf of the admin such as creating new users or modifying site settings, and potentially deface the website or redirect visitors to phishing sites. The persistence of the payload means that a single successful exploitation can lead to continuous compromise until the malicious content is manually removed from the database.
This vulnerability aligns with CWE-79, which classifies Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. Furthermore, it maps directly to MITRE ATT&CK technique T1059.007, indicating JavaScript execution within a browser environment, and can be leveraged for credential theft under the tactic of Credential Access (T1539). The failure to validate input against configuration standards also reflects CWE-20, Improper Input Validation, highlighting a fundamental gap in the application's security design where trust boundaries are not properly enforced between user inputs and system configurations.
To mitigate this risk, immediate action is required by upgrading the Easy Form Builder plugin to version 4.2.0 or later, which addresses these validation deficiencies. In environments where an upgrade is not immediately feasible, administrators should implement strict input sanitization at the application level for all form submission endpoints, ensuring that only expected data types and formats are accepted. Additionally, enforcing output encoding on any dynamic content rendered in administrative interfaces can prevent script execution even if malicious data persists in the database. Regular security audits of third-party plugins and adherence to secure coding practices such as those outlined by OWASP are essential for maintaining a robust defense posture against similar injection-based attacks.