Answer in brief
CVE-2026-55430 records a Medium severity (CVSS 5.8) vulnerability in Coder's subdomain workspace app routing trusts unauthenticated X-Forwarded-Host header, enabling cross-app data access. The current sources do not mark it as known exploited. The current feed maps coder/coder (generic), github.com/coder/coder/v2 (go), github.com/coder/coder/v2 (go), github.com/coder/coder/v2 (go) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps coder/coder (generic), github.com/coder/coder/v2 (go), github.com/coder/coder/v2 (go), github.com/coder/coder/v2 (go) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| coder/codergeneric | >= 2.34.0, < 2.34.2 || >= 2.33.0, < 2.33.8 || >= 2.30.0, < 2.32.7 || < 2.29.17 | Not reported |
| github.com/coder/coder/v2go | >=2.34.0,<2.34.2 | 2.34.2 |
| github.com/coder/coder/v2go | >=2.33.0,<2.33.8 | 2.33.8 |
| github.com/coder/coder/v2go | >=2.30.0,<2.32.7 | 2.32.7 |
| github.com/coder/coder/v2go | <2.29.17 | 2.29.17 |
Published upstream
Jul 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 6, 2026
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.
Quoted source text, attributed separately from HOL analysis.