The vulnerability arises from djust's tenant isolation mechanism relying on threading.local() storage set only by HTTP middleware, which does not apply to live WebSocket or SSE connections. As a result, get_current_tenant() returns None during these live interactions, causing tenant-aware QuerySet managers to fail open by returning unfiltered querysets and exposing data from all tenants to unauthorized users holding the socket. Additionally, threading.local was shared across connections on async executor threads, exacerbating the issue. The fix in djust 1.0.7 replaces threading.local with contextvars.ContextVar to provide per-async-task tenant isolation, binds tenant context around WebSocket/SSE mounts and dispatches, and enforces fail-closed behavior by returning empty querysets under default STRICT_MODE. A system check warns if STRICT_MODE is disabled. No workarounds are available for live paths.

This vulnerability allows unauthorized disclosure of tenant data across WebSocket or SSE connections by failing to enforce tenant isolation, leading to potential exposure of sensitive information from all tenants to any user connected via the live path. The CVSS score of 7.7 reflects high confidentiality impact with no integrity or availability impact. There are no known exploits in the wild.

A fixed version, djust 1.0.7, is available and should be applied to remediate this vulnerability. The fix moves tenant storage to context-local variables and enforces fail-closed behavior for tenant-aware querysets. No known workarounds exist for the live WebSocket/SSE path, so upgrading is the recommended and necessary mitigation.