djust: WebSocket/runtime reconstructed request omits the client Host, causing host/subdomain TenantResolvers to misresolve the tenant on the live path

Summary

djust provides Phoenix LiveView-style reactive server-side rendering for Django with Rust-powered performance. Prior to version 1.0.7, the WebSocket `handle_mount` and `ViewRuntime._build_request` rebuild an `HttpRequest` via `RequestFactory().get(...)` with no `HTTP_HOST`, so `request.get_host()` defaulted to `"testserver"` on the live path. Host/subdomain/domain `TenantResolver`s then misresolved the tenant — `None` on the live path while the HTTP path resolved correctly. With `STRICT_MODE=False` the tenant-scoped managers returned unscoped rows (cross-tenant disclosure); with the default they returned an empty queryset (broken tenancy). This is fixed in djust 1.0.7. The handshake Host is extracted from the ASGI scope, validated against `ALLOWED_HOSTS` (the same logic as the CSWSH Origin gate, parsed with Django's `split_domain_port` so malformed Hosts are rejected at the boundary), and propagated — with the TLS scheme — into the reconstructed request, so live-path tenant resolution matches HTTP exactly. There is no known workaround on the live path short of upgrading. Users are most exposed when combined with `STRICT_MODE=False`.

Timeline

1. Sep 16, 2026, 10:08 PM UTCCVE published
2. Sep 17, 2026, 5:10 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Sep 17, 2026, 7:23 PM UTCRecord last updated

Affected versions

• djust-org djust

  fixed in 1.0.7

• djustPyPI

  fixed in 1.0.7

• djustPyPI

  fixed in 1.0.7

References 2