1 files changed, 6 insertions, 0 deletions
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 1942e2ad30..439bfe5919 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -606,6 +606,12 @@ class PresenceHandler(BaseHandler):
         status_msg = state.get("status_msg", None)
         presence = state["presence"]
 
+        valid_presence = (
+            PresenceState.ONLINE, PresenceState.UNAVAILABLE, PresenceState.OFFLINE
+        )
+        if presence not in valid_presence:
+            raise SynapseError(400, "Invalid presence state")
+
         user_id = target_user.to_string()
 
         prev_state = yield self.current_state_for_user(user_id)