CVE-2026-33638 Ech0 authenticated user-list exposed data via public `/api/allusers` endpoint
Unauthenticated attackers can access the public /api/allusers endpoint to enumerate users and view profile metadata in Ech0.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33638?
CVE-2026-33638 is a medium-severity missing authorization vulnerability in lin-snow Ech0, published on 26 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Ech0 is an open-source, self-hosted publishing platform for personal idea sharing. Prior to version 4.2.0, `GET /api/allusers` is mounted as a public endpoint and returns user records without authentication. This allows remote unauthenticated user enumeration and exposure of user profile metadata. A fix is available in v4.2.0.
Weakness: CWE-862
Which versions are affected by CVE-2026-33638?
3 open source packages ship an affected version, including github.com/lin-snow/ech0. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/lin-snow/ech0 Go | All versions | 1.4.8-0.20260322121226-acbf1fd71011 |
github.com/lin-snow/ech0 Go | All versions | 1.4.8-0.20260322121226-acbf1fd71011 |
github.com/lin-snow/ech0 Go | All versions | 1.4.8-0.20260322121226-acbf1fd71011 |
Products include Ech0 Ech0.
How do I fix CVE-2026-33638?
Upgrade github.com/lin-snow/ech0 to 1.4.8-0.20260322121226-acbf1fd71011 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-33638 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33638 exists.
Other vulnerabilities in lin-snow Ech0
Sources
Also known as GHSA-m983-7426-5hrj, GO-2026-4838.