diff --git a/src/akkudoktoreos/core/dataabc.py b/src/akkudoktoreos/core/dataabc.py
index a1d55b7..f272e3f 100644
--- a/src/akkudoktoreos/core/dataabc.py
+++ b/src/akkudoktoreos/core/dataabc.py
@@ -1224,14 +1224,14 @@ class DataImportMixin:
                     # We jump back by 1 hour
                     # Repeat the value(s) (reuse value index)
                     for i in range(interval_steps_per_hour):
-                        logger.debug(f"{i+1}: Repeat at {next_time} with index {value_index}")
+                        logger.debug(f"{i + 1}: Repeat at {next_time} with index {value_index}")
                         timestamps_with_indices.append((next_time, value_index))
                         next_time = next_time.add(seconds=interval.total_seconds())
                 else:
                     # We jump forward by 1 hour
                     # Drop the value(s)
                     logger.debug(
-                        f"{i+1}: Skip {interval_steps_per_hour} at {next_time} with index {value_index}"
+                        f"{i + 1}: Skip {interval_steps_per_hour} at {next_time} with index {value_index}"
                     )
                     value_index += interval_steps_per_hour
 
diff --git a/src/akkudoktoreos/server/eos.py b/src/akkudoktoreos/server/eos.py
index e9bc047..828ef30 100755
--- a/src/akkudoktoreos/server/eos.py
+++ b/src/akkudoktoreos/server/eos.py
@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 
 import argparse
+import html
 import os
 import subprocess
 import sys
@@ -129,8 +130,8 @@ def create_error_page(
     return (
         ERROR_PAGE_TEMPLATE.replace("STATUS_CODE", status_code)
         .replace("ERROR_TITLE", error_title)
-        .replace("ERROR_MESSAGE", error_message)
-        .replace("ERROR_DETAILS", error_details)
+        .replace("ERROR_MESSAGE", html.escape(error_message))
+        .replace("ERROR_DETAILS", html.escape(error_details))
     )