CVE-2026-113442 in Fluid-Form
Summary
by MITRE • 10/20/2026
Values entered by visitors were placed into the HTML summary email without being escaped. An unauthenticated attacker could use this to inject HTML into an email that is shown to the recipient.
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Analysis
by VulDB Data Team • 10/20/2026
The vulnerability described constitutes a classic case of Cross-Site Scripting, specifically manifesting as Stored or Persistent XSS within an administrative notification system. The core technical flaw lies in the application's failure to properly sanitize user-supplied input before embedding it into dynamically generated HTML content. When visitors submit values through forms or other interactive elements on the website, these inputs are captured and subsequently inserted directly into the body of summary emails sent to administrators or other recipients. Because the email client renders this content as HTML rather than plain text, any malicious scripts embedded within those fields will execute in the context of the recipient's browser environment upon opening the message. This lack of output encoding allows an unauthenticated attacker to bypass standard access controls and inject arbitrary web script code into a trusted communication channel.
From a technical perspective, this issue represents a failure in input validation and output encoding principles. The application treats user data as executable content rather than safe text data. In modern web development frameworks, this is typically addressed by applying context-aware escaping to all dynamic variables before they are rendered in HTML contexts. Without such safeguards, special characters like angle brackets, quotes, and ampersands retain their structural meaning within the DOM of the email client. This enables the attacker to construct payloads that can steal session cookies, hijack administrative sessions, perform actions on behalf of the victim, or redirect users to phishing sites. The severity is heightened by the fact that no authentication is required to trigger this vulnerability, making it easily exploitable by any internet user with minimal technical expertise.
The operational impact of this vulnerability extends beyond simple script execution. Since the malicious content is stored in emails sent to potentially privileged accounts such as system administrators or support staff, successful exploitation can lead to significant compromise of organizational security posture. Attackers can use this vector for credential harvesting via fake login pages hosted on external servers, thereby gaining unauthorized access to sensitive backend systems. Furthermore, if the email client supports active content like JavaScript, attackers may exfiltrate data from the recipient's local environment or manipulate the display of other emails in the inbox. This undermines trust in internal communications and can serve as a foothold for more advanced persistent threats targeting high-value targets within the organization.
To mitigate this vulnerability, immediate remediation steps must focus on implementing robust input validation and strict output encoding. All user-supplied data destined for HTML contexts should be encoded using appropriate libraries that handle character escaping based on the specific context of insertion. For email generation systems, it is advisable to send emails as plain text whenever possible, or if HTML formatting is required, ensure that all dynamic content undergoes rigorous sanitization against a whitelist of allowed tags and attributes rather than relying solely on blacklist approaches. Additionally, implementing Content Security Policy headers within any web-based interfaces can help mitigate the impact of successful XSS attacks by restricting script execution sources. Regular security testing including automated static analysis and manual penetration tests should be integrated into the development lifecycle to detect such encoding flaws early before deployment.
This vulnerability aligns with CWE-79: Improper Neutralization of Input During Web Page Generation, commonly known as Cross-site Scripting (XSS). It also maps to MITRE ATT&CK technique T1059.007: Command and Control via HTML Injection, where attackers use injected scripts to establish communication channels or exfiltrate data from compromised systems. Addressing this issue requires a shift in development practices toward secure coding standards that prioritize defense-in-depth strategies for all user-facing inputs regardless of their perceived risk level.