Vulnerability Description
File Viewer is a browser-native viewer for Office, PDF, CAD, archive, and other files in private and internal web applications. Prior to @file-viewer/doc 2.3.1 and msdoc-viewer 0.2.2, the legacy DOC renderer emitted document-controlled hyperlink targets into generated HTML after character escaping but without restricting URL schemes. A crafted legacy DOC file could place javascript:, vbscript:, data:, or another unsafe scheme in a rendered link, and script could execute in the embedding application's origin when a user clicked the link. The fix blocks external document links by default, allows only HTTP(S), mail, telephone, safe relative URLs, and internal bookmarks when external links are explicitly enabled, and applies mount-boundary sanitization as defense in depth. This issue is fixed in @file-viewer/doc 2.3.1 and msdoc-viewer 0.2.2.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/flyfish-dev/file-viewer/commit/ef045680f8d9830a3eee9612f7df46
- https://github.com/flyfish-dev/file-viewer/releases/tag/v2.3.1
- https://github.com/flyfish-dev/file-viewer/security/advisories/GHSA-3753-m2x2-q6
FAQ
What is CVE-2026-91127?
CVE-2026-91127 is a vulnerability with a CVSS score of 8.2 (HIGH). File Viewer is a browser-native viewer for Office, PDF, CAD, archive, and other files in private and internal web applications. Prior to @file-viewer/doc 2.3.1 and msdoc-viewer 0.2.2, the legacy DOC r...
How severe is CVE-2026-91127?
CVE-2026-91127 has been rated HIGH with a CVSS base score of 8.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-91127?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.