CVE-2026-61599: Djust Djust Has An Unauthenticated Arbitrary Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-7prp-2623-8g45",
  "modified" : "2026-09-16T22:09:38Z",
  "published" : "2026-09-16T22:09:38Z",
  "aliases" : [ "CVE-2026-61599" ],
  "summary" : "djust has an unauthenticated arbitrary module import via the WebSocket/SSE view-mount path",
  "details" : "### Impact\nThe djust live transport resolves the LiveView to mount from a **client-supplied dotted path** by calling `__import__(module_path, ...)`. The module is imported — running its **top-level code (import side effects)** — *before* the framework checks that the resolved object is a `LiveView` subclass and *before* any per-view authentication. The `LIVEVIEW_ALLOWED_MODULES` allowlist that should contain this is **fail-open** (`if allowed_modules:` — skipped when the setting is unset, the framework default) and uses loose `startswith` matching.\n\nAn **unauthenticated** WebSocket client (the WS handshake does not require auth; per-view auth runs only after import + instantiate) can therefore send a `mount` / `live_redirect_mount` / `url_change` frame (or an SSE mount) with `view = \"<any.importable.module>.AnyName\"` and cause the server to import — and execute the top-level code of — **any importable Python module by name**.\n\n**Consequences:** server-side execution of arbitrary importable modules' import-time side effects by an unauthenticated client (effectively RCE-by-proxy on any host that has a side-effectful importable module), denial of service (import bombs / expensive dependency trees), and a module/class **enumeration oracle** via distinct error strings.\n\nReproduced end-to-end: an unauthenticated `WebsocketCommunicator` `mount` frame with the allowlist unset imported and executed a sentinel non-LiveView module before the \"not a LiveView subclass\" rejection.\n\n### Affected code\n- `python/djust/websocket.py` `handle_mount` (`__import__` of the client `view`)\n- `python/djust/runtime.py` `ViewRuntime.dispatch_mount` / `_instantiate_view` (SSE + `url_change` path)\n- `python/djust/sse.py` SSE mount\n\nThreat-model entry T4 (`docs/audits/websocket-auth-2026-06.md`) previously noted the default-open allowlist but understated the impact as mere LiveView-class probing; the real primitive is arbitrary-module import + top-level code execution, independent of whether the target is a LiveView.\n\n### Patches\nFixed by a fail-**closed** resolution gate (`djust._view_resolution.is_view_import_allowed`): a client view path resolves only if (a) its module is **already loaded** (`sys.modules` — so resolving runs no new code; URL-routed views loaded by URLconf at startup keep working with zero config) or (b) it matches `LIVEVIEW_ALLOWED_MODULES` on a **module-segment boundary** (explicit opt-in for lazily-imported views). The gate runs **before** `__import__` at all three sinks (+ defense-in-depth inside `_instantiate_view`).\n\n### Workarounds\nSet `LIVEVIEW_ALLOWED_MODULES` to the narrow list of modules that contain your mountable LiveView classes. (Note: pre-patch the allowlist is `startswith`-matched and the import still precedes the subclass check, so this is mitigation, not a complete fix.)\n\n### References\nReproducer + finding writeup retained privately by the maintainer.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "djust"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.0.7"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/djust-org/djust/security/advisories/GHSA-7prp-2623-8g45"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/djust-org/djust"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/djust-org/djust/releases/tag/v1.0.7"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-470" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-16T22:09:38Z",
    "nvd_published_at" : null
  }
}