CVE-2026-49446Cosmos: Authentication bypass via forward-auth header smuggling on Constellation tunnel in Cosmos-Server
- 6.1MediumCVSS base score
- 0.30%Exploitation in 30 daysEPSS · top 77% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
- https://github.com/azukaar/Cosmos-Server/security/advisories/GHSA-2rx5-2g7j-2659 (opens in a new tab)x_refsource_CONFIRMexploit
Timeline
ID reserved
By GitHub_M
- 4 months later
· 4 months later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium6.1 | CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N |
| NVDNVD · Deferred | 3.1 | Medium6.1 | CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N |
- EPSS (exploitation in 30 days)
- 0.30% · top 77% of all CVEs (15 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.1.
Affected products
- affected < 0.22.19
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Gogithub.com/azukaar/cosmos-serverGHSA-2rx5-2g7j-2659 (opens in a new tab)
References
References3
- https://github.com/azukaar/Cosmos-Server/security/advisories/GHSA-2rx5-2g7j-2659 (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/azukaar/Cosmos-Server/commit/59c561d686c8f9843b3e092b50f6346c481d8bbf (opens in a new tab)x_refsource_MISC
- https://github.com/azukaar/Cosmos-Server/releases/tag/v0.22.19 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-78588 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-2rx5-2g7j-2659 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-49446)Record last updated .