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CVE PROGRAM SOURCE RECORD6.1 Medium

CVE-2026-49446

Cosmos: Authentication bypass via forward-auth header smuggling on Constellation tunnel in Cosmos-Server

Description

Cosmos provides users the ability self-host a home server by acting as a secure gateway to your application, as well as a server manager. Prior to 0.22.19, tokenMiddleware in src/proxy/routerGen.go can return through the Constellation tunnel bypass before removing x-cosmos-user, x-cosmos-role, x-cosmos-user-role, and x-cosmos-mfa headers and before invoking AdminOnlyWithRedirect. An attacker with a valid x-cstln-auth API key for an enrolled device who reaches Cosmos through the Constellation Nebula tunnel can supply a chosen x-cosmos-user value to a route with AuthEnabled enabled when the upstream application trusts that forward-auth header. The request can bypass Cosmos JWT, password, MFA, and AdminOnly checks, allowing user impersonation and admin-tier reads or writes exposed by the proxied application. This issue is fixed in version 0.22.19.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

azukaar Cosmos-Server

  • < 0.22.19affected

References