CVE-2026-40262
Note Mark has Stored XSS via Unrestricted Asset Upload
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.
Timeline
ID reserved
By GitHub_M
- 6 days later
· 6 days later
Published
- 2 days later
· 2 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High8.7 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N |
| NVDNVD · Deferred | 3.1 | High8.7 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N |
- EPSS (exploitation in 30 days)
- 0.31% · top 76% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.7.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Gogithub.com/enchant97/note-mark/backendGHSA-9pr4-rf97-79qh (opens in a new tab)
References (3)
- https://github.com/enchant97/note-mark/security/advisories/GHSA-9pr4-rf97-79qh (opens in a new tab)x_refsource_CONFIRM
- https://github.com/enchant97/note-mark/commit/6bb62842ccb956870b9bf183629eba95e326e5e3 (opens in a new tab)x_refsource_MISC
- https://github.com/enchant97/note-mark/releases/tag/v0.19.2 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-9pr4-rf97-79qh (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-40262)Record last updated .