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Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVE-2026-46426

Low
0/10

Summary

The file upload endpoint `POST /api/attachments/process` does not enforce active-content restrictions for authenticated users. The checks for dangerous file extensions (`html`, `svg`, `js`, `php`, etc.) are conditionally wrapped inside `if (isPublicUser)` or `if (isPublicUser || !env.SELF_HOSTED)`, meaning any authenticated builder can upload executable web content -- SVG files with inline `<script>` tags, HTML pages with JavaScript, `.js` modules -- which are then stored in the object store (MinIO/S3) with their correct MIME types (`image/svg+xml`, `text/html`, `application/javascript`). When the resulting signed URL is opened by any app user, the browser executes the payload. This issue affects versions prior to 3.38.2.

  • LOW
  • NETWORK
  • LOW
  • CHANGED
  • REQUIRED
  • LOW
  • HIGH
  • NONE

CWE-79 - Cross Site Scripting

Cross-Site Scripting, commonly referred to as XSS, is the most dominant class of vulnerabilities. It allows an attacker to inject malicious code into a pregnable web application and victimize its users. The exploitation of such a weakness can cause severe issues such as account takeover, and sensitive data exfiltration. Because of the prevalence of XSS vulnerabilities and their high rate of exploitation, it has remained in the OWASP top 10 vulnerabilities for years.

References

Advisory Timeline

  • Published