Summary
djust authentication bypass: a loginrequired / onmount LiveView mount redirect does not close the WebSocket, allowing an unauthenticated client to dispatch event-handler calls
Workarounds
Upgrade to 1.0.4. If you cannot upgrade immediately, on affected versions ensure that every @event_handler on a gated LiveView independently verifies the request user is authenticated and authorized (e.g. check request.user.is_authenticated / permissions at the top of each handler), since the framework does not re-check after mount on < 1.0.4. Alternatively, override the consumer's handle_mount to await self.close(code=4403) after emitting an auth redirect.
Proof of concept
Using Channels' WebsocketCommunicator against LiveViewConsumer.as_asgi() with an anonymous scope, mount a login_required view: the server emits a navigate frame but the socket stays open. Sending a subsequent {"type":"event", "handler":"<mutating_handler>", ...} frame reaches the handler and executes it without an authenticated session. On 1.0.4 the socket is closed with code 4403 immediately after the redirect and the event frame is rejected. (Regression test: tests/test_ws_auth_close_socket.py.)
Credits
Discovered internally during the djust v1.1.0 WebSocket-auth security review.
Impact
djust's LiveViewConsumer mounts a LiveView over a WebSocket. When a view is gated (login_required / permission_required, or an on_mount hook that returns a redirect) and the connecting user is not authorized, the consumer sent the client a {"type":"navigate","to":...} redirect frame and then returned, without closing the socket and without clearing self.view_instance. Only the PermissionDenied branch closed the connection (close(4403)).
A real browser obeys the navigate frame and leaves, hiding the problem. A raw WebSocket client that ignores the redirect keeps an open, mounted socket. Because handle_event did not re-check authentication/authorization after mount, that client could then send {"type":"event", ...} frames and invoke any @event_handler method on the gated view with no authenticated session, an authentication bypass on the live mutation path.
Who is affected: apps that expose LiveViews gated by login_required / permission_required / a redirecting on_mount hook, where the gated view's event handlers perform sensitive reads or mutations and do not independently re-verify the user. Exploitation requires a non-browser WebSocket client and knowledge (or enumeration) of the view path and event names.
A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.
CVE-2026-55571 has a CVSS score of 8.2 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.0.4); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Fixed in djust 1.0.4 (commit 1ae8aa9, PR #1780). Both the auth-redirect and on_mount-hook-redirect branches of handle_mount now send the navigate frame and then close(code=4403) and clear self.view_instance, mirroring the existing PermissionDenied branch. Public / authorized mounts are unchanged. The same path is reachable via handle_live_redirect_mount (which delegates to handle_mount) and is covered by the same fix.
1.0.4 also adds an opt-in defense-in-depth control, LIVEVIEW_CONFIG['reauth_on_event'] = True (default OFF), which re-resolves the user from the session and re-runs the view's auth check on every event for gated views.
Frequently Asked Questions
- What is CVE-2026-55571? CVE-2026-55571 is a high-severity missing authentication for critical function vulnerability in djust (pip), affecting versions < 1.0.4. It is fixed in 1.0.4. A critical operation is accessible without requiring any authentication.
- How severe is CVE-2026-55571? CVE-2026-55571 has a CVSS score of 8.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of djust are affected by CVE-2026-55571? djust (pip) versions < 1.0.4 is affected.
- Is there a fix for CVE-2026-55571? Yes. CVE-2026-55571 is fixed in 1.0.4. Upgrade to this version or later.
- Is CVE-2026-55571 exploitable, and should I be worried? Whether CVE-2026-55571 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-55571 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-55571? Upgrade
djustto 1.0.4 or later.