CVE-2026-40262CWE-434CWE-79

Note Mark has Stored XSS via Unrestricted Asset Upload

High · published April 16, 2026

CVSS v3.1
8.7
EPSS
0%
Percentile
34.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.7 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00416 · 34.8th percentile
Weaknesses
CWE-434 · Unrestricted Upload of File with Dangerous Type; CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-04-16T23:51Z
EPSS history
Timeline
  • 16 APR 23:51Z
    Note Mark has Stored XSS via Unrestricted Asset Upload
    cvelistv5