diff --git a/src/main/java/eu/siacs/conversations/entities/Conversation.java b/src/main/java/eu/siacs/conversations/entities/Conversation.java
index 8b02d8be5..8b359713a 100644
--- a/src/main/java/eu/siacs/conversations/entities/Conversation.java
+++ b/src/main/java/eu/siacs/conversations/entities/Conversation.java
@@ -576,7 +576,9 @@ public class Conversation extends AbstractEntity implements Blockable, Comparabl
 		values.put(CREATED, created);
 		values.put(STATUS, status);
 		values.put(MODE, mode);
-		values.put(ATTRIBUTES, attributes.toString());
+		synchronized (this.attributes) {
+			values.put(ATTRIBUTES, attributes.toString());
+		}
 		return values;
 	}