CVE-2026-55430: Coder allows organizations to provision remote develop
CVE-2026-55430 analysis covering impact, affected products, versions, remediation, and cross-checked defender guidance.
CVE-2026-55430 is a vulnerability published by NVD on 7/8/2026.
What happened
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.
Affected products and versions
- coder coder unspecified version (before 2.29.17)
- coder coder unspecified version (from 2.30.0 before 2.32.7)
- coder coder unspecified version (from 2.33.0 before 2.33.8)
- coder coder unspecified version (from 2.34.0 before 2.34.2)
Severity and weakness
CVSS: MEDIUM 5.8. Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N.
Weaknesses: CWE-345, CWE-441.
Known exploitation
No CISA KEV entry is currently attached to the NVD record.
What defenders should do
- Identify whether the affected product and version range exists in production.
- Review vendor advisories and release notes before change windows.
- Patch, upgrade, disable the vulnerable component, or apply vendor mitigations.
- Verify the running version after deployment, not only the package inventory.
Official and supporting references
- https://github.com/coder/coder/pull/26204
- https://github.com/coder/coder/releases/tag/v2.29.17
- https://github.com/coder/coder/releases/tag/v2.32.7
- https://github.com/coder/coder/releases/tag/v2.33.8
- https://github.com/coder/coder/releases/tag/v2.34.2
- https://github.com/coder/coder/security/advisories/GHSA-5g4w-3vw9-478w