CVE-2026-61598

djust: Client mass-assignment of arbitrary view attributes via the default dj-model update_model handler

Workarounds

Set allowed_model_fields explicitly on every view using dj-model (or subclassing LiveView) to the minimal list of bindable fields; do not keep authorization/ownership state in public view attributes that share the view with dj-model bindings.

References

Reproducer + finding writeup retained privately by the maintainer.

djust.mixins.model_binding.ModelBindingMixin provides a default update_model event handler and is part of the LiveView base MRO, so every LiveView exposes it. It setattrs a view attribute whose name is client-supplied (field), gated only by: reject _-prefixed names; reject a 14-entry denylist of framework internals (FORBIDDEN_MODEL_FIELDS); optional allowed_model_fields which defaults to None = allow all; and hasattr existence.

Result: a client can set any public, existing view attribute, not just the fields actually bound with dj-model= in the rendered template. The denylist covers framework plumbing but nothing about developer business/authz state, and the allowlist is opt-in (off by default). A developer who binds one dj-model="search" input and also keeps self.account_id / self.is_admin / self.total_price as view state does not realize a client can set ALL of them via {type:event, event:"update_model", params:{field, value}} over the WebSocket. Type coercion matches the target attribute's type (so "true" -> bool True), aiding the attacker.

Severity High for apps that hold authorization/ownership/business state in public view attributes (the normal djust pattern) -> state tampering / IDOR / authz-flag manipulation; Low otherwise. Default-on across every LiveView. For a public (no-login) view an anonymous client can mass-assign; for an authenticated view a logged-in user can tamper their own session's view state (the IDOR/authz vector when downstream handlers act on it without re-authorizing).

Reproduced: a view with account_id/is_admin/total_price (none bound with dj-model) had all three set via update_model calls.

Kodem intelligence

Already deployed Kodem?

Restrict the default handler to fields actually exposed via dj-model=: have the template renderer record the bound-field set per render and reject any field outside it (preferred, secure + zero-config); or make allowed_model_fields fail-closed (required). Keep FORBIDDEN_MODEL_FIELDS only as defense-in-depth. Add a regression that a non-dj-model public attribute (e.g. is_admin) is rejected while a bound field still updates.

1. What is CVE-2026-61598? CVE-2026-61598 is a high-severity security vulnerability in djust (pip), affecting versions < 1.0.7. It is fixed in 1.0.7.
2. Which versions of djust are affected by CVE-2026-61598? djust (pip) versions < 1.0.7 is affected.
3. Is there a fix for CVE-2026-61598? Yes. CVE-2026-61598 is fixed in 1.0.7. Upgrade to this version or later.
4. Is CVE-2026-61598 exploitable, and should I be worried? Whether CVE-2026-61598 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
5. What actually determines whether CVE-2026-61598 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.
6. How do I fix CVE-2026-61598? Upgrade djust to 1.0.7 or later.