Ech0 Scope Bypass: profile:read Access Token Can Change Admin Password and Escalate to Unrestricted Session

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary The PUT /user endpoint is protected by RequireScopes("profile:read"), which is a read-only scope. However, the endpoint performs write operations including password changes. An attacker who obtains an admin's restricted profile:read access token can change the admin's password, then login to receive an unrestricted session token that bypasses all scope enforcement. Details The scope enforcement system defines granular scopes (e.g., echo:read, echo:write, admin:user) but has no profile:write scope. The PUT /user route is protected only by profile:read: The RequireScopes middleware bypasses all scope checks for session tokens, and for access tokens only verifies the token contains the listed scopes: The UpdateUser service checks user.IsAdmin but does not verify the token's scope is sufficient for write operations: After the password is changed, the attacker logs in via POST /login which calls issueUserToken → CreateClaims, producing a session token with Type: "session"…

Published by the source

10 Apr 2026, 19:49 UTC

Last modified by the source

10 Apr 2026, 19:49 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-hm2h-wwwh-g49x

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# Patch Next advisory brief: GHSA-hm2h-wwwh-g49x

Advisory: Ech0 Scope Bypass: profile:read Access Token Can Change Admin Password and Escalate to Unrestricted Session
IDs: GHSA-hm2h-wwwh-g49x
Record: https://patchnext.com/advisories/ghsa-hm2h-wwwh-g49x (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/lin-snow/ech0 4.4.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/lin-snow/ech0: affected < 4.4.3; fixed in 4.4.3

## Suggested inspection (read-only)
- Go github.com/lin-snow/ech0: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/lin-snow/ech0.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-hm2h-wwwh-g49x (GitHub-reviewed advisory GHSA-hm2h-wwwh-g49x lists affected ranges: Go github.com/lin-snow/ech0 >=0 <4.4.3)

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