CVE-2026-101921 in WPForms Plugin
Summary
by MITRE • 10/10/2026
The WPForms – AI Form Builder for WordPress – Contact Forms, Payment Forms, Survey Form, Quiz & More plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'attacker-chosen key referenced by the smart tag (e.g. "x")' parameter in all versions up to, and including, 2.0.2.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. Exploitation requires that a site administrator has previously saved a form whose description embeds a {query_var} Smart Tag inside an iframe srcdoc attribute and has enabled Show Description on a public-facing page.
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Analysis
by VulDB Data Team • 10/10/2026
The WPForms plugin, widely utilized for creating contact forms, payment gateways, surveys, quizzes, and other interactive elements within WordPress environments, contains a critical security flaw identified as Reflected Cross-Site Scripting. This vulnerability exists in all versions up to and including 2.0.2.1 and stems from insufficient input sanitization and output escaping mechanisms when processing the attacker-chosen key referenced by smart tags, specifically parameters such as x within query variables. The core technical issue lies in how the plugin handles dynamic content insertion via its Smart Tag system. When a form description embeds a {query_var} Smart Tag inside an iframe srcdoc attribute, the application fails to properly validate or escape user-supplied input before rendering it into the HTML context of the page. This lack of rigorous validation allows malicious actors to inject arbitrary web scripts that are executed by the victim's browser upon interaction with the compromised content.
The operational impact of this vulnerability is significant due to its potential for widespread exploitation in public-facing WordPress sites. Because the flaw permits unauthenticated attackers to execute arbitrary JavaScript code, it can lead to severe consequences including session hijacking, credential theft, defacement of web pages, and redirection to malicious domains. The attack vector relies on social engineering tactics where an attacker must trick a user into performing a specific action, such as clicking on a specially crafted link that triggers the execution of the injected script. This requirement for user interaction classifies the vulnerability under Reflected Cross-Site Scripting rather than Stored XSS, although the persistence of the vulnerable code in the form configuration adds complexity to the exploitation chain. The presence of an iframe srcdoc attribute further complicates security controls as iframes often operate with different origin policies and may bypass certain browser-based protections depending on their implementation details.
From a standards perspective, this vulnerability aligns closely with CWE-79 Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. Specifically, it represents an instance where input validation is insufficient at the point of use rather than during initial ingestion. Additionally, the exploitation technique maps to MITRE ATT&CK techniques related to Client-Side Injection and potentially Command and Control if used for beaconing or data exfiltration through browser-based channels. The requirement that a site administrator must have previously saved a form with specific configurations means that while any user can trigger the payload, the initial setup requires privileged access, highlighting the importance of securing administrative interfaces as well as public-facing endpoints.
Mitigation strategies should focus on immediate remediation and long-term security hardening. Administrators running WPForms versions up to 2.0.2.1 are strongly advised to upgrade to the latest patched version immediately upon release by the vendor. In cases where upgrading is not feasible, temporary workarounds include disabling the Show Description feature for forms that utilize Smart Tags within iframe srcdoc attributes or removing such configurations entirely until a patch is applied. Implementing Content Security Policy headers can also help mitigate the impact of successful XSS attacks by restricting the sources from which scripts can be loaded and executed. Furthermore, developers should enforce strict input validation on all user-supplied data before it enters any dynamic context and ensure that output escaping is consistently applied based on the specific encoding context such as HTML attribute values or script blocks. Regular security audits and penetration testing of WordPress plugins are essential to identify similar flaws in other components that may share these architectural weaknesses.