CVE-2026-55430— Coder's subdomain workspace app routing trusts unauthenticated X-Forwarded-Host header, enabling cross-app data access

Coder's subdomain workspace app routing trusts unauthenticated X-Forwarded-Host header, enabling cross-app data access

Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, the workspace app proxy resolves the target app from `httpapi.RequestHost()` which prefers the `X-Forwarded-Host` header over the real `Host` header. No middleware strips `X-Forwarded-Host` before routing and the header is not browser-forbidden so client-side JavaScript can set it on `fetch()` calls. Practical exploitation requires subdomain app routing (wildcard hostname) enabled, a victim who visits the attacker's shared app and a deployment whose upstream proxy does not strip `X-Forwarded-Host`. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 trusts `X-Forwarded-Host` only from configured trusted proxies and otherwise resolves the routing host from the verified request host. As a workaround, place an upstream reverse proxy that strips or overwrites `X-Forwarded-Host` on untrusted requests.

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N

对数据真实性的验证不充分

Coder 输入验证错误漏洞

Coder是Coder组织开源的一个可以在公共或私有云基础设施中设置开发环境的应用程序。 Coder存在安全漏洞，该漏洞源于对X-Forwarded-Host头验证不当，可能导致客户端JavaScript设置恶意标头，路由解析时绕过主机验证。以下版本受到影响：2.29.17之前版本、2.30.0至2.32.7之前版本、2.33.0至2.33.8之前版本和2.34.0至2.34.2之前版本。

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