CVE-2025-46236 is a Stored Cross-Site Scripting (XSS) vulnerability classified under CWE-79, affecting Link Software LLC's HTML Forms product up to version 1.5.2. The vulnerability arises due to improper neutralization of user-supplied input during web page generation, allowing malicious scripts to be stored and subsequently executed in the context of users accessing the affected forms. Stored XSS vulnerabilities occur when an attacker injects malicious code that is permanently stored on the target server (e.g., in a database or form data) and delivered to users without proper sanitization or encoding. This can lead to session hijacking, credential theft, defacement, or distribution of malware. The vulnerability affects HTML Forms, a product used to create and manage web forms, which are commonly integrated into websites for data collection, user interaction, and business processes. No patches or fixes have been published yet, and no known exploits are currently observed in the wild. The vulnerability was publicly disclosed on April 22, 2025, and is categorized as medium severity. The lack of a CVSS score requires an independent severity assessment based on the potential impact and exploitability factors. Stored XSS vulnerabilities typically require no authentication to exploit if the form is publicly accessible, and user interaction is limited to visiting a compromised page. The scope includes all users interacting with the vulnerable forms, potentially exposing sensitive information or enabling further attacks within the affected web applications.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on Link Software LLC's HTML Forms for customer-facing or internal web applications. Exploitation could lead to unauthorized access to user sessions, theft of sensitive data such as personal information or credentials, and potential compromise of internal networks if attackers leverage the XSS to escalate privileges or deploy further payloads. Organizations in sectors such as finance, healthcare, e-commerce, and government are particularly at risk due to the sensitive nature of the data handled and regulatory requirements like GDPR. Additionally, reputational damage and legal consequences could arise from data breaches facilitated by this vulnerability. The medium severity rating suggests a moderate risk, but the actual impact depends on the deployment context, the sensitivity of the data processed by the forms, and the presence of compensating controls such as Web Application Firewalls (WAFs) or Content Security Policies (CSP). Since no known exploits are currently active, proactive mitigation is critical to prevent future attacks.

1. Immediate code review and input validation: Developers should implement strict input validation and output encoding on all user-supplied data within HTML Forms to neutralize potentially malicious scripts. Use context-aware encoding libraries that handle HTML, JavaScript, and URL contexts appropriately. 2. Deploy Content Security Policy (CSP): Configure CSP headers to restrict the execution of inline scripts and loading of resources from untrusted sources, mitigating the impact of any injected scripts. 3. Use Web Application Firewalls (WAFs): Employ WAF solutions capable of detecting and blocking XSS payloads targeting HTML Forms, providing an additional layer of defense. 4. Monitor and audit form inputs: Implement logging and monitoring to detect unusual input patterns or repeated injection attempts, enabling early detection of exploitation attempts. 5. Patch management: Engage with Link Software LLC for updates or patches addressing this vulnerability. If unavailable, consider temporary workarounds such as disabling vulnerable form features or replacing the product with alternatives. 6. User awareness and training: Educate users and administrators about the risks of XSS and encourage cautious behavior when interacting with web forms, especially those that handle sensitive data. 7. Regular security testing: Conduct penetration testing and code audits focusing on input handling and output encoding to identify and remediate similar vulnerabilities proactively.