Medium 6.1Published Sep 15, 2026

CVE-2026-49446Cosmos: Authentication bypass via forward-auth header smuggling on Constellation tunnel in Cosmos-Server

Updated under an hour ago (2026-10-19 06:20 UTC)

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It affects azukaar Cosmos-Server. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for azukaar Cosmos-Server

Exploited in the last 30 days

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.

CVSS: 6.1 MEDIUM (v3.1, CNA)CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-285, CWE-290
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Sep 15, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

azukaar Cosmos-Server azukaar:cosmos_server (from the name)	before 0.22.19	CNA record

References

https://github.com/azukaar/Cosmos-Server/security/advisories/GHSA-2rx5-2g7j-2659x-refsource-confirm
https://github.com/azukaar/Cosmos-Server/commit/59c561d686c8f9843b3e092b50f6346c481d8bbfx-refsource-misc
https://github.com/azukaar/Cosmos-Server/releases/tag/v0.22.19x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.