CVE-2026-61589 djust: WebSocket/runtime reconstructed request omits the client Host, causing host/subdomain TenantResolvers to misresolve the tenant on the live path
Attackers can access cross-tenant data in djust when STRICT_MODE is disabled due to missing Host header in WebSocket requests.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-61589?
CVE-2026-61589 is a medium-severity vulnerability in djust-org djust, published on 16 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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`.
Which versions are affected by CVE-2026-61589?
3 open source packages ship an affected version, including djust.
| Package | Affected | Fixed in |
|---|---|---|
djust PyPI | All versions | 1.0.7 |
djust PyPI | All versions | 1.0.7 |
djust PyPI | All versions | 1.0.7 |
How do I fix CVE-2026-61589?
Upgrade djust to 1.0.7 or later.
Is CVE-2026-61589 being exploited?
There is no known exploitation of CVE-2026-61589 in the wild and no public exploit code.
Sources
Also known as GHSA-v9rj-xjfv-xj9r, PYSEC-2026-4046.