---
title: "CVE-2026-91127: File Viewer - Stored XSS"
description: "File Viewer @file-viewer/doc < 2.3.1 and msdoc-viewer < 0.2.2 contain a stored XSS caused by unsafe URL schemes in legacy DOC renderer hyperlink targets, letting attackers execute scripts in the embedding application's origin, exploit requires user clicking crafted link."
url: https://panop.io/threat-heartbeat/CVE-2026-91127/
---

# CVE-2026-91127 File Viewer - Stored XSS

File Viewer @file-viewer/doc < 2.3.1 and msdoc-viewer < 0.2.2 contain a stored XSS caused by unsafe URL schemes in legacy DOC renderer hyperlink targets, letting attackers execute scripts in the embedding application's origin, exploit requires user clicking crafted link.

CVSS base score 8.2 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.40% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-91127)

## Details

Type

Stored XSS

Impact

Client Script Exec

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N

Published

18 September 2026

Updated

15 October 2026

Weakness

[CWE-79](https://cwe.mitre.org/data/definitions/79.html)

## Vendor fix

Update to @file-viewer/doc 2.3.1 and msdoc-viewer 0.2.2 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-91127](https://nvd.nist.gov/vuln/detail/CVE-2026-91127)
- [https://github.com/flyfish-dev/file-viewer/commit/ef045680f8d9830a3eee9612f7df46a734361b07](https://github.com/flyfish-dev/file-viewer/commit/ef045680f8d9830a3eee9612f7df46a734361b07)
- [https://github.com/flyfish-dev/file-viewer/releases/tag/v2.3.1](https://github.com/flyfish-dev/file-viewer/releases/tag/v2.3.1)
- [https://github.com/flyfish-dev/file-viewer/security/advisories/GHSA-3753-m2x2-q623](https://github.com/flyfish-dev/file-viewer/security/advisories/GHSA-3753-m2x2-q623)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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