CVE-2026-49446— Cosmos: Authentication bypass via forward-auth header smuggling on Constellation tunnel in Cosmos-Server
Quick assessment
Affected
azukaar Cosmos-Server
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Cosmos 允许用户自行托管一个主服务器，它既可以作为应用程序的安全网关，也可以作为服务器管理器。 在 0.22.19 版本之前，位于 中的 在移除 、 、 和 请求头以及调用 之前，就会通过 Constellation 隧道返回。 对于拥有已注册设备的有效 API 密钥的攻击者，如果通过 Constellation Nebula 隧道访问 Cosmos，并且上游应用信任这些转发认证请求头，攻击者可以向启用了 的路由提供自选的 值。 这样，请求将绕过 Cosmos 的 JWT、密码、多因素认证（MFA）以及 检查
Possible ATT&CK Techniques 1 AI
T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-49446
Vulnerability Information
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Vulnerability Title
Cosmos: Authentication bypass via forward-auth header smuggling on Constellation tunnel in Cosmos-Server
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
授权机制不恰当
Source: CVE Program / CVE List V5
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| azukaar | Cosmos-Server | < 0.22.19 | - |
|
II. Public POCs for CVE-2026-49446
| # | POC Description | Source Link | Shenlong Link |
|---|
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Vendor Advisories for CVE-2026-49446 (1)
IV. Related Vulnerabilities
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V. Comments for CVE-2026-49446
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