CVE-2026-49446

MediumCVSS 6.1

Published: 15/09/2026(UTC)Updated: 30/09/2026(UTC)Translated: 15/09/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.30%

20th percentile - higher than 20% of all known CVEs

Summary

In Cosmos 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.

Risk Assessment

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.

Recommendation

Update Cosmos to version 0.22.19, where the issue is fixed.

Other vulnerabilities in Cosmos

CVE-2026-49447Medium
Cosmos version 0.22.18 discloses Constellation device metadata to any requester supplying a non-empty Authorization header. The handler strips the 'Bearer ' prefix but never validates the token or uses it in the database query.

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS