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TI-2026-29056 Aliases CVE-2026-40262GHSA-9pr4-rf97-79qh

Note Mark has Stored XSS via Unrestricted Asset Upload

Priority HIGH 73CWE-434Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
Low
Impact type
Code execution, Cross-site scripting
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-434 and CWE-79.

Summary

Note Mark is an open-source note-taking application. In versions 0.19.1 and prior, the asset delivery handler serves uploaded files inline and relies on magic-byte detection for content type, which does not identify text-based formats such as HTML, SVG, or XHTML. These files are served with an empty Content-Type, no X-Content-Type-Options: nosniff header, and inline disposition, allowing browsers to sniff and render active content. An authenticated user can upload an HTML or SVG file containing JavaScript as a note asset, and when a victim navigates to the asset URL, the script executes under the application's origin with access to the victim's authenticated session and API actions. This issue has been fixed in version 0.19.2.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00309 23rd percentileScored 2026-11-07
Fix Fixed note-mark (enchant97): 0.19.2github.com/enchant97/note-mark/backend (Go): 0.0.0-20260411145018-6bb62842ccb9

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
enchant97note-markbefore 0.19.20.19.2Patch availableCNA
—github.com/enchant97/note-mark/backend (Go)before 0.0.0-20260411145018-6bb62842ccb90.0.0-20260411145018-6bb62842ccb9Patch availableGHSA-9pr4-rf97-79qh
  • note-mark Vendorenchant97 Affected before 0.19.2 Fixed in 0.19.2 Patch available CNA
  • github.com/enchant97/note-mark/backend (Go) Vendor— Affected before 0.0.0-20260411145018-6bb62842ccb9 Fixed in 0.0.0-20260411145018-6bb62842ccb9 Patch available GHSA-9pr4-rf97-79qh

Remediation

  • Fix · CNA note-mark (enchant97) Fixed in 0.19.2
  • Fix · GHSA-9pr4-rf97-79qh github.com/enchant97/note-mark/backend (Go) Fixed in 0.0.0-20260411145018-6bb62842ccb9 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-40262
  2. 2026-10-03 Alias added: GHSA-9pr4-rf97-79qh

References

Advisory 1

Other 4

  • TI-2026-32452 Note Mark: JWT Secret Weakness allows Full Account Takeover via token forgery CVSS 3.1CRITICAL 10.0
  • TI-2026-30126 Note Mark: OIDC-registered users authenticated by submitting password "null" CVSS 3.1CRITICAL 9.4
  • TI-2026-37275 Note Mark: Path traversal via unsanitized book/note slug in migrate export (sibling of GHSA-g49p) CVSS 4.0HIGH 8.6
  • TI-2026-32451 Note Mark: Arbitrary File Write via Path Traversal in Asset Names Leading to Remote Code Execution CVSS 4.0HIGH 8.6
  • TI-2026-37276 Note Mark: Unauthenticated disclosure of soft-deleted note metadata via deleted=true on public books in note-mark CVSS 3.1MEDIUM 5.3
  • TI-2026-30127 Note Mark: Unauthenticated read of notes and assets in soft-deleted public books CVSS 3.1MEDIUM 5.3
See all 8 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences