Vulnerability · Published Apr 16, 2026 · Assigned by GitHub_M
CVE-2026-40262Note Mark has Stored XSS via Unrestricted Asset Upload
High 8.7
In plain English
A high-severity cross-site scripting in note-mark from enchant97. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/enchant97/note-mark/backend | 0.0.0-20260411145018-6bb62842ccb9 | GHSA-9pr4-rf97-79qh |
| Go | github.com/enchant97/note-mark/backend | 0.0.0-20260411145018-6bb62842ccb9 | GO-2026-5295 |
Affected products (as reported)
Weakness: CWE-79, CWE-434 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N