CVE-2026-40262: Note Mark has Stored XSS via Unrestricted Asset Upload

April 13, 2026 (updated April 24, 2026)

A stored same-origin XSS vulnerability allows any authenticated user to upload an HTML, SVG, or XHTML file as a note asset and have it executed in a victim’s browser under the application’s origin. Because the application serves these files inline without a safe content type and without nosniff, browsers can sniff and render active content, giving the attacker access to authenticated Note Mark API actions as the victim.

References

github.com/advisories/GHSA-9pr4-rf97-79qh
github.com/enchant97/note-mark/commit/6bb62842ccb956870b9bf183629eba95e326e5e3
github.com/enchant97/note-mark/releases/tag/v0.19.2
github.com/enchant97/note-mark/security/advisories/GHSA-9pr4-rf97-79qh
nvd.nist.gov/vuln/detail/CVE-2026-40262

Code Behaviors & Features

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