diff --git a/backend/open_webui/models/chats.py b/backend/open_webui/models/chats.py
index 3ae7112f3e..c559932bcd 100644
--- a/backend/open_webui/models/chats.py
+++ b/backend/open_webui/models/chats.py
@@ -765,15 +765,20 @@ class ChatTable:
                     )
 
             elif dialect_name == "postgresql":
-                # PostgreSQL relies on proper JSON query for search
+                # PostgreSQL doesn't allow null bytes in text. We filter those out by checking
+                # the JSON representation for \u0000 before attempting text extraction
                 postgres_content_sql = (
                     "EXISTS ("
                     "    SELECT 1 "
                     "    FROM json_array_elements(Chat.chat->'messages') AS message "
-                    "    WHERE LOWER(message->>'content') LIKE '%' || :content_key || '%'"
+                    "    WHERE message->'content' IS NOT NULL "
+                    "    AND (message->'content')::text NOT LIKE '%\\u0000%' "
+                    "    AND LOWER(message->>'content') LIKE '%' || :content_key || '%'"
                     ")"
                 )
                 postgres_content_clause = text(postgres_content_sql)
+                # Also filter out chats with null bytes in title
+                query = query.filter(text("Chat.title::text NOT LIKE '%\\x00%'"))
                 query = query.filter(
                     or_(
                         Chat.title.ilike(bindparam("title_key")),