CVE-2026-96355 in Webform
Summary
by MITRE • 10/22/2026
Improper Neutralization of Special Elements Used in a Template Engine vulnerability in Drupal Webform allows Code Injection. 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 vulnerability represents a critical security flaw within the Drupal Webform module, specifically classified under CWE-94 as Improper Control of Generation of Code (Code Injection). This issue arises due to insufficient sanitization and validation of user-supplied input before it is processed by the template engine. In web application architectures, template engines are designed to separate presentation logic from business logic, but when they accept dynamic content without proper neutralization of special elements such as script tags or server-side execution directives, attackers can inject malicious code that executes within the context of the vulnerable application.
The technical root cause lies in the handling of form data where specific characters and sequences are not adequately escaped or filtered before being passed to the rendering layer. When a user submits a Webform containing specially crafted payloads, these inputs bypass existing security checks because the validation logic fails to recognize them as dangerous template directives or executable scripts. Consequently, the application interprets this malicious input as legitimate code, leading to arbitrary command execution on the server side if the underlying system allows it, or cross-site scripting in client-side contexts depending on how the output is rendered and encoded by subsequent layers of the web stack.
From an operational perspective, the impact of this vulnerability is severe for organizations relying on Drupal Webforms for data collection, customer interaction, or internal workflows. An attacker can exploit this flaw to achieve remote code execution, potentially gaining full control over the affected server environment. This leads to unauthorized access to sensitive database records, modification of website content, defacement, and further lateral movement within the network infrastructure. The vulnerability affects Webform versions ranging from 0.0.0 up through 6.2.12, as well as version 6.3.0 to 6.3.1, indicating a persistent failure in input validation practices across multiple major releases of this widely used module.
In terms of industry standard mapping, this vulnerability aligns with the MITRE ATT&CK technique T1190 Exploit Public-Facing Application, where adversaries leverage vulnerabilities in internet-facing software to gain initial access. It also correlates with CWE-74 Improper Neutralization Special Elements in Output Used by a Downstream Component, highlighting the failure to sanitize data before it is processed by downstream components like template engines. The lack of proper input validation exemplifies common weaknesses found in legacy or poorly maintained web applications that do not adhere to secure coding standards such as OWASP Top 10 guidelines regarding injection flaws.
To mitigate this risk, immediate action must be taken to update the Drupal Webform module to a version newer than 6.3.1 where these input validation issues have been addressed by the development team. Organizations should also implement web application firewalls configured with rulesets capable of detecting and blocking template injection patterns in HTTP requests. Additionally, developers should enforce strict output encoding and context-aware escaping for all dynamic content rendered through templates to prevent similar vulnerabilities from manifesting even if other modules are updated. Regular security audits and static code analysis tools can help identify such improper neutralization issues early in the development lifecycle before deployment to production environments.