{"items":[{"id":"NVI-00014132","kind":"vulnerability","title":"Phoenix: Presence keys colliding with `Object.prototype` members break existence checks","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-63mc-hw7g-86rr","CVE-2026-56812"],"plain_summary":"GitHub lists this reviewed advisory for phoenix, phoenix, phoenix, phoenix, phoenix. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-4e14d771157e184fe4e8625139693efc"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-4e14d771157e184fe4e8625139693efc","url":"https://github.com/advisories/GHSA-63mc-hw7g-86rr","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-63mc-hw7g-86rr","publisher":"GitHub Advisory Database","observed_at":"2026-11-02T02:21:29.477Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-4e14d771157e184fe4e8625139693efc"],"technology":"phoenix","known_exclusions":[],"conditions_summary":"### Summary\n\nThe Phoenix JavaScript presence client (`assets/js/phoenix/presence.js`) tests whether a presence already exists using a bare truthiness check (`state[key]`) rather than an own-property check. Because applications commonly track presences under a client-supplied username or id, the presence key can be attacker-controlled. A user who joins a channel and picks a key that names an `Object.prototype` member (`__proto__`, `constructor`, `toString`, `hasOwnProperty`, and similar) makes the lookup return the inherited `Object.prototype` object instead of `undefined`, which is truthy. The code then reads `.metas.map(...)` off it and throws an uncaught `TypeError`, breaking presence sync for every viewer of that channel topic. Any authenticated channel participant can trigger it.\n\n### Details\n\nThe victim is any browser subscribed to a presence channel. When it receives the server's `presence_state` message, it invokes `Presence.syncState`, which iterates the incoming presences and checks whether each one already exists locally via `let currentPresence = state[key]`. `state` is a plain object inheriting from `Object.prototype`. For an ordinary key like `alice`, `state[\"alice\"]` ","public_affected_ranges":[">= 1.2.0-rc.0, < 1.5.15"]},{"certainty":"source_listed","source_ids":["sr-4e14d771157e184fe4e8625139693efc"],"technology":"phoenix","known_exclusions":[],"conditions_summary":"### Summary\n\nThe Phoenix JavaScript presence client (`assets/js/phoenix/presence.js`) tests whether a presence already exists using a bare truthiness check (`state[key]`) rather than an own-property check. Because applications commonly track presences under a client-supplied username or id, the presence key can be attacker-controlled. A user who joins a channel and picks a key that names an `Object.prototype` member (`__proto__`, `constructor`, `toString`, `hasOwnProperty`, and similar) makes the lookup return the inherited `Object.prototype` object instead of `undefined`, which is truthy. The code then reads `.metas.map(...)` off it and throws an uncaught `TypeError`, breaking presence sync for every viewer of that channel topic. Any authenticated channel participant can trigger it.\n\n### Details\n\nThe victim is any browser subscribed to a presence channel. When it receives the server's `presence_state` message, it invokes `Presence.syncState`, which iterates the incoming presences and checks whether each one already exists locally via `let currentPresence = state[key]`. `state` is a plain object inheriting from `Object.prototype`. For an ordinary key like `alice`, `state[\"alice\"]` ","public_affected_ranges":[">= 1.6.0-rc.0, < 1.6.17"]},{"certainty":"source_listed","source_ids":["sr-4e14d771157e184fe4e8625139693efc"],"technology":"phoenix","known_exclusions":[],"conditions_summary":"### Summary\n\nThe Phoenix JavaScript presence client (`assets/js/phoenix/presence.js`) tests whether a presence already exists using a bare truthiness check (`state[key]`) rather than an own-property check. Because applications commonly track presences under a client-supplied username or id, the presence key can be attacker-controlled. A user who joins a channel and picks a key that names an `Object.prototype` member (`__proto__`, `constructor`, `toString`, `hasOwnProperty`, and similar) makes the lookup return the inherited `Object.prototype` object instead of `undefined`, which is truthy. The code then reads `.metas.map(...)` off it and throws an uncaught `TypeError`, breaking presence sync for every viewer of that channel topic. Any authenticated channel participant can trigger it.\n\n### Details\n\nThe victim is any browser subscribed to a presence channel. When it receives the server's `presence_state` message, it invokes `Presence.syncState`, which iterates the incoming presences and checks whether each one already exists locally via `let currentPresence = state[key]`. `state` is a plain object inheriting from `Object.prototype`. For an ordinary key like `alice`, `state[\"alice\"]` ","public_affected_ranges":[">= 1.7.0-rc.0, < 1.7.24"]},{"certainty":"source_listed","source_ids":["sr-4e14d771157e184fe4e8625139693efc"],"technology":"phoenix","known_exclusions":[],"conditions_summary":"### Summary\n\nThe Phoenix JavaScript presence client (`assets/js/phoenix/presence.js`) tests whether a presence already exists using a bare truthiness check (`state[key]`) rather than an own-property check. Because applications commonly track presences under a client-supplied username or id, the presence key can be attacker-controlled. A user who joins a channel and picks a key that names an `Object.prototype` member (`__proto__`, `constructor`, `toString`, `hasOwnProperty`, and similar) makes the lookup return the inherited `Object.prototype` object instead of `undefined`, which is truthy. The code then reads `.metas.map(...)` off it and throws an uncaught `TypeError`, breaking presence sync for every viewer of that channel topic. Any authenticated channel participant can trigger it.\n\n### Details\n\nThe victim is any browser subscribed to a presence channel. When it receives the server's `presence_state` message, it invokes `Presence.syncState`, which iterates the incoming presences and checks whether each one already exists locally via `let currentPresence = state[key]`. `state` is a plain object inheriting from `Object.prototype`. For an ordinary key like `alice`, `state[\"alice\"]` ","public_affected_ranges":[">= 1.8.0-rc.0, < 1.8.9"]}],"null_published_at":"2026-11-02T10:00:37.212Z","source_updated_at":"2026-09-03T20:30:34.000Z","source_disclosed_at":"2026-09-03T20:30:33.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-02T02:21:29.477Z"}],"next_cursor":null,"snapshot_revision":"42594"}