CVE-2026-96357 in Webform Module
Summary
by MITRE • 10/22/2026
Improper Neutralization of Input During Web Page Generation ("Cross-site Scripting") vulnerability in Drupal Webform allows Stored XSS. This issue affects Webform versions: from 0.0.0 to 6.2.12, from 6.3.0 to 6.3.1.
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Analysis
by VulDB Data Team • 10/22/2026
The identified security flaw represents a classic instance of Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting or XSS. Specifically, this vulnerability manifests within the Drupal Webform module, allowing for Stored XSS attacks rather than reflected ones. This distinction is critical because stored vulnerabilities persist on the target server, meaning that malicious scripts are saved in a database or file and subsequently served to every user who views the affected content. The flaw impacts versions of the Webform module ranging from 0.0.0 up through version 6.2.12, as well as the specific range from 6.3.0 to 6.3.1. These older iterations lack sufficient sanitization mechanisms for user-supplied data before it is rendered in a web browser context.
From a technical perspective, the vulnerability arises because the application fails to properly validate or encode input fields within the Webform submission process. When an attacker submits a form containing malicious JavaScript code, the system accepts this input without applying necessary neutralization techniques such as HTML entity encoding or strict output escaping. Consequently, when another user accesses the page displaying the stored form data, their browser executes the embedded script in the context of the vulnerable website. This behavior aligns directly with CWE-79, which defines Cross-site Scripting (XSS) as a weakness where web applications include untrusted data in a way that allows an attacker to execute malicious scripts in a victim's browser.
The operational impact of this vulnerability is severe due to its stored nature. Unlike reflected XSS, which requires tricking a user into clicking a specially crafted link, stored XSS automatically affects all visitors who view the compromised content. An attacker can exploit this to steal session cookies, hijack administrative accounts, deface websites, or redirect users to malicious sites designed for phishing or malware distribution. In environments where Drupal Webform is used for sensitive data collection, such as contact forms or internal portals, the breach of trust and potential loss of confidentiality are significant concerns. The persistence of the payload means that remediation requires not only patching the software but also cleaning any existing malicious entries from the database to prevent continued exposure.
This vulnerability maps closely to MITRE ATT&CK technique T1059.007, which covers JavaScript execution in web browsers as part of Command and Scripting Interpreter tactics. Attackers leverage this capability to perform client-side attacks that bypass server-side security controls by executing code within the victim's trusted environment. The lack of input validation allows the attacker to inject arbitrary scripts that interact with the Document Object Model (DOM) of the target page, potentially accessing sensitive information stored in local storage or cookies associated with the domain.
To mitigate this risk, organizations running affected versions of Drupal Webform must immediately upgrade to a patched version outside the specified vulnerable ranges. The maintainers have released updates that implement proper input sanitization and output encoding practices consistent with secure coding standards. Additionally, implementing a Content Security Policy (CSP) can provide an additional layer of defense by restricting the sources from which scripts are allowed to execute, thereby mitigating the impact even if some XSS vectors remain unpatched temporarily. Regular security audits and code reviews focusing on input validation logic are recommended to prevent similar flaws in future development cycles.