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CVE-2026-49446GHSA-2RX5-2G7J-2659GO-2026-6123

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

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 0.22.19
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: poc
  • Automatable: no
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • azukaar Cosmos-Server

    fixed in 0.22.19

  • github.com/azukaar/cosmos-serverGo

    fixed in 0.22.19

References 3

GitHub · azukaar/Cosmos-Server