XSS in Hi.Events via Malicious Event Title

Executive Summary

CVE-2026-60119 is a stored cross-site scripting (XSS) vulnerability in the Hi.Events application, affecting versions up to v1.10.0-beta. The vulnerability allows authenticated attackers with event creation or edit permissions to inject arbitrary HTML and JavaScript into event titles.

The issue occurs because the application embeds user-controlled event titles directly into JavaScript contexts without proper escaping. Specifically, the event title is serialized using JSON.stringify() and inserted into inline script tags, such as in application/ld+json structured data blocks or as part of a server-side rehydrated state variable (window.__REHYDRATED_STATE__).

Since JSON.stringify() does not escape the </script> sequence, an attacker can craft an event title containing </script> followed by malicious JavaScript. When other users, including unauthenticated visitors or administrators, view the public event page, the injected script executes in their browsers.

Useful 0 Not Useful 0

Detection Guidance

Detecting this vulnerability involves checking for the presence of unescaped event titles in the Hi.Events application that could break out of script contexts. Since the vulnerability arises from improper escaping of event titles embedded in inline script tags, you can inspect the application's frontend code or network responses for signs of malicious payloads.

• Review the event titles in the Hi.Events application for suspicious content, such as the presence of '</script>' sequences or other JavaScript payloads. This can be done by querying the database or inspecting the event pages directly.
• Use browser developer tools to inspect the HTML source of event pages. Look for inline script tags containing 'application/ld+json' or 'window.__REHYDRATED_STATE__' and check if the event title is embedded without proper escaping (e.g., unescaped '<', '>', or '&' characters).
• Check the version of Hi.Events running on your system. If it is v1.10.0-beta or earlier, it is vulnerable. You can verify the version by checking the application's configuration files or release notes.
• Monitor network traffic for unusual JavaScript execution when loading event pages. Tools like Burp Suite or OWASP ZAP can help intercept and analyze responses for signs of XSS payloads.

Useful 0 Not Useful 0

Impact Analysis

If you are a user of the Hi.Events application, this vulnerability could impact you in several ways:

• Attackers with event creation or edit permissions can execute malicious scripts in your browser when you view a compromised event page. This could lead to unauthorized actions being performed on your behalf, such as stealing session cookies, redirecting you to phishing sites, or performing actions within the application without your consent.
• Unauthenticated visitors or administrators viewing a public event page with a malicious title could unknowingly execute the attacker's script, potentially exposing sensitive data or compromising their accounts.
• The vulnerability could be used to deface event pages, spread malware, or launch further attacks against other users of the application.

If you are an administrator or maintainer of the Hi.Events application, this vulnerability could also lead to reputational damage, loss of user trust, and potential legal consequences if sensitive data is exposed.

Useful 0 Not Useful 0

Compliance Impact

This vulnerability could impact compliance with several common standards and regulations, depending on the context in which the Hi.Events application is used:

• GDPR (General Data Protection Regulation): If the Hi.Events application processes personal data of EU citizens, this vulnerability could lead to unauthorized access or disclosure of that data. Under GDPR, organizations must implement appropriate technical measures to protect personal data. A failure to prevent XSS attacks could be seen as a violation of these requirements, potentially resulting in fines or other penalties.
• HIPAA (Health Insurance Portability and Accountability Act): If the Hi.Events application is used in a healthcare context to manage or display protected health information (PHI), this vulnerability could lead to unauthorized access or disclosure of PHI. HIPAA requires covered entities to implement safeguards to protect the confidentiality, integrity, and availability of PHI. An XSS vulnerability that exposes PHI could be considered a violation of these requirements.
• PCI DSS (Payment Card Industry Data Security Standard): If the Hi.Events application handles payment card information, this vulnerability could lead to the theft of cardholder data. PCI DSS requires organizations to protect cardholder data from unauthorized access. An XSS vulnerability that exposes such data could result in non-compliance with PCI DSS requirements.

In general, this vulnerability undermines the security controls required by these regulations, potentially leading to data breaches, loss of sensitive information, and non-compliance with legal obligations.

Useful 0 Not Useful 0

Mitigation Strategies

To mitigate this vulnerability, follow these immediate steps:

• Upgrade the Hi.Events application to version 1.11.0-beta or later, as this version includes fixes for the XSS vulnerability. The upgrade addresses the improper escaping of event titles in inline script contexts.
• If upgrading is not immediately possible, apply the patches or fixes provided in the GitHub pull request #1260. This includes implementing the `stripControlCharacters` method and `htmlSafeJsonStringify` utility to safely serialize JSON data for inline script tags.
• Temporarily restrict event creation or editing permissions to trusted users only. This reduces the risk of attackers injecting malicious payloads into event titles.
• Audit existing event titles for malicious content, such as '</script>' sequences or other JavaScript payloads. Remove or sanitize any suspicious titles to prevent exploitation.
• Monitor the application for unusual activity, such as unexpected script execution or data exfiltration attempts. Implement logging and alerting for suspicious behavior.
• Review the application's code to ensure that all user-controlled data embedded in inline script tags is properly escaped. Replace any instances of raw JSON.stringify() with a safe serialization routine that escapes critical characters like '<', '>', and '&'.

Useful 0 Not Useful 0