diff --git a/backend/open_webui/migrations/versions/8452d01d26d7_add_chat_message_table.py b/backend/open_webui/migrations/versions/8452d01d26d7_add_chat_message_table.py
index d17194045..631dceba1 100644
--- a/backend/open_webui/migrations/versions/8452d01d26d7_add_chat_message_table.py
+++ b/backend/open_webui/migrations/versions/8452d01d26d7_add_chat_message_table.py
@@ -124,6 +124,13 @@ def upgrade() -> None:
 
             timestamp = message.get("timestamp", now)
 
+            # Normalize timestamp: convert ms to seconds, validate range
+            if timestamp > 10_000_000_000:
+                timestamp = timestamp // 1000
+            # Must be after 2020 and not too far in the future
+            if timestamp < 1577836800 or timestamp > now + 86400:
+                timestamp = now
+
             try:
                 conn.execute(
                     sa.insert(chat_message_table).values(
diff --git a/backend/open_webui/models/chat_messages.py b/backend/open_webui/models/chat_messages.py
index 371e90db3..8c9d326a3 100644
--- a/backend/open_webui/models/chat_messages.py
+++ b/backend/open_webui/models/chat_messages.py
@@ -18,6 +18,29 @@ from sqlalchemy import (
     Index,
 )
 
+####################
+# Helpers
+####################
+
+
+def _normalize_timestamp(timestamp: int) -> float:
+    """Normalize and validate timestamp. Returns current time if invalid."""
+    now = time.time()
+
+    # Convert milliseconds to seconds if needed
+    if timestamp > 10_000_000_000:
+        timestamp = timestamp / 1000
+
+    # Validate: must be after 2020 and not in the future (with 1 day tolerance)
+    min_valid = 1577836800  # 2020-01-01 00:00:00 UTC
+    max_valid = now + 86400  # 1 day in the future (clock skew tolerance)
+
+    if timestamp < min_valid or timestamp > max_valid:
+        return now
+
+    return timestamp
+
+
 ####################
 # ChatMessage DB Schema
 ####################
@@ -455,15 +478,15 @@ class ChatMessageTable:
             # Group by date -> model -> count
             daily_counts: dict[str, dict[str, int]] = {}
             for timestamp, model_id in results:
-                date_str = datetime.fromtimestamp(timestamp).strftime("%Y-%m-%d")
+                date_str = datetime.fromtimestamp(_normalize_timestamp(timestamp)).strftime("%Y-%m-%d")
                 if date_str not in daily_counts:
                     daily_counts[date_str] = {}
                 daily_counts[date_str][model_id] = daily_counts[date_str].get(model_id, 0) + 1
 
             # Fill in missing days
             if start_date and end_date:
-                current = datetime.fromtimestamp(start_date)
-                end_dt = datetime.fromtimestamp(end_date)
+                current = datetime.fromtimestamp(_normalize_timestamp(start_date))
+                end_dt = datetime.fromtimestamp(_normalize_timestamp(end_date))
                 while current <= end_dt:
                     date_str = current.strftime("%Y-%m-%d")
                     if date_str not in daily_counts:
@@ -497,15 +520,15 @@ class ChatMessageTable:
             # Group by hour -> model -> count
             hourly_counts: dict[str, dict[str, int]] = {}
             for timestamp, model_id in results:
-                hour_str = datetime.fromtimestamp(timestamp).strftime("%Y-%m-%d %H:00")
+                hour_str = datetime.fromtimestamp(_normalize_timestamp(timestamp)).strftime("%Y-%m-%d %H:00")
                 if hour_str not in hourly_counts:
                     hourly_counts[hour_str] = {}
                 hourly_counts[hour_str][model_id] = hourly_counts[hour_str].get(model_id, 0) + 1
 
             # Fill in missing hours
             if start_date and end_date:
-                current = datetime.fromtimestamp(start_date).replace(minute=0, second=0, microsecond=0)
-                end_dt = datetime.fromtimestamp(end_date)
+                current = datetime.fromtimestamp(_normalize_timestamp(start_date)).replace(minute=0, second=0, microsecond=0)
+                end_dt = datetime.fromtimestamp(_normalize_timestamp(end_date))
                 while current <= end_dt:
                     hour_str = current.strftime("%Y-%m-%d %H:00")
                     if hour_str not in hourly_counts: