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CVE-2026-91127

File Viewer: DOM XSS via unsafe hyperlink schemes in the legacy DOC renderer

CVSS score

8.2

EPSS probability

%0.4

Risk score

0.0

Published

24 d ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Patch status has not yet been verified

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Impact on My Inventory

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-91127 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

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.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-91127 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1flyfish-devfile-viewer View
2@file-viewerdoc View
3flyfish-devmsdoc-viewer View
4npm@file-viewer/doc View
5npmmsdoc-viewer View
Total affected vendors: 3|Products: 5

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
8.2CVSS 3.x—Vector not publishedGitHub Advisory
8.2CVSS V31HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:NNVD
8.2CVSS V3_1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:NCVE CNA
0.0CVSS 4.0—Vector not publishedGitHub Advisory

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-91127 is associated with the following CWEs:

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')CWE-83: Common Weakness Enumeration Entry CWE-83

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-91127 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
UserGerekiyor

Official Sources and Advisories

https://github.com/flyfish-dev/file-viewer/security/advisories/GHSA-3753-m2x2-q623vendor-advisoryhttps://github.com/flyfish-dev/file-viewer/commit/ef045680f8d9830a3eee9612f7df46a734361b07vendor-advisoryhttps://github.com/flyfish-dev/file-viewer/releases/tag/v2.3.1vendor-advisoryhttps://github.com/advisories/GHSA-3753-m2x2-q623vendor-advisory

CVSS Vector Radar Chart

8.2 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.RequiredConfidentialityLowIntegrityLowAvailabilityNone

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User Interaction—
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)Low
Availability (Erişilebilirlik)None

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Follow the vendor

F
flyfish-dev logo
flyfish-dev
@
@file-viewer logo
@file-viewer
N
npm logo
npm

Weakness Type (CWE & CAPEC)

CWE-79 CWE-83

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