CVE-2026-40265 Note Mark has Broken Access Control on Asset Download
Unauthenticated attackers can access private note assets by guessing IDs, exposing sensitive data in Note Mark applications.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40265?
CVE-2026-40265 is a medium-severity missing authorization vulnerability in enchant97 note-mark, published on 16 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Note Mark is an open-source note-taking application. In versions 0.19.1 and prior, the asset download endpoint at /api/notes/{noteID}/assets/{assetID} is registered without authentication middleware, and the backend query does not verify ownership or book visibility. An unauthenticated user who knows a valid note ID and asset ID can retrieve the full contents of private note assets without authentication, regardless of whether the associated book is public or private. This issue has been fixed in version 0.19.2.
Weakness: CWE-862
Which versions are affected by CVE-2026-40265?
3 open source packages ship an affected version, including github.com/enchant97/note-mark/backend.
| Package | Affected | Fixed in |
|---|---|---|
github.com/enchant97/note-mark/backend Go | All versions | 0.0.0-20260411145023-6593898855ad |
github.com/enchant97/note-mark/backend Go | All versions | 0.0.0-20260411145023-6593898855ad |
github.com/enchant97/note-mark/backend Go | All versions | 0.0.0-20260411145023-6593898855ad |
How do I fix CVE-2026-40265?
Upgrade github.com/enchant97/note-mark/backend to 0.0.0-20260411145023-6593898855ad or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-40265 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40265 exists.
Sources
Also known as GHSA-p5w6-75f9-cc2p, GO-2026-5530.