GHSA-63MC-HW7G-86RR Phoenix: Presence keys colliding with `Object.prototype` members break existence checks

Summary The Phoenix JavaScript presence client assets/js/phoenix/presence.js tests whether a presence already exists using a bare truthiness check statekey rather than an own-property check. Because applications commonly track presences under a client-supplied username or id, the presence key can...

Improper Check for Unusual or Exceptional Conditions

Overview org.webjars.npm:phoenix is a The official JavaScript client for the Phoenix web framework. Affected versions of this package are vulnerable to Improper Check for Unusual or Exceptional Conditions via the syncState and syncDiff presence reconciliation code in assets/js/phoenix/presence.js...

CVE-2026-56812 Phoenix JavaScript presence client crashes on presence keys colliding with Object.prototype members in Presence.syncState/syncDiff

Improper Check for Unusual or Exceptional Conditions vulnerability in phoenixframework phoenix Presence JavaScript client allows an attacker with ordinary channel access to cause a persistent client-side denial of service against every viewer of a presence channel topic. This vulnerability is...