diff --git a/backend/open_webui/internal/migrations/019_encrypt_user_valves.py b/backend/open_webui/internal/migrations/019_encrypt_user_valves.py
index 69c259884e..009a3cc2a9 100644
--- a/backend/open_webui/internal/migrations/019_encrypt_user_valves.py
+++ b/backend/open_webui/internal/migrations/019_encrypt_user_valves.py
@@ -29,6 +29,7 @@ Some examples (model - class or model name)::
 from contextlib import suppress
 
 import json
+import logging
 
 import peewee as pw
 from peewee_migrate import Migrator
@@ -38,20 +39,31 @@ from open_webui.utils.valve_encryption import encrypt_user_valves
 with suppress(ImportError):
     import playhouse.postgres_ext as pw_pext
 
+log = logging.getLogger(__name__)
+
 
 def migrate(migrator: Migrator, database: pw.Database, *, fake=False):
     """Encrypt existing plaintext user valves in user.settings."""
-    cursor = database.execute_sql('SELECT "id", "settings" FROM "user" WHERE "settings" IS NOT NULL')
+    User = migrator.orm["user"]
 
-    for user_id, settings_raw in cursor.fetchall():
+    for user in User.select().where(User.settings.is_null(False)):
+        settings_raw = user.settings
         if not settings_raw:
             continue
 
-        settings = (
-            json.loads(settings_raw)
-            if isinstance(settings_raw, str)
-            else settings_raw
-        )
+        try:
+            settings = (
+                json.loads(settings_raw)
+                if isinstance(settings_raw, str)
+                else settings_raw
+            )
+        except (json.JSONDecodeError, TypeError):
+            log.warning("Skipping user %s: malformed settings JSON", user.id)
+            continue
+
+        if not isinstance(settings, dict):
+            log.warning("Skipping user %s: settings is not a dict", user.id)
+            continue
 
         changed = False
 
@@ -69,27 +81,35 @@ def migrate(migrator: Migrator, database: pw.Database, *, fake=False):
                     changed = True
 
         if changed:
-            database.execute_sql(
-                'UPDATE "user" SET "settings" = %s WHERE "id" = %s',
-                (json.dumps(settings), user_id),
-            )
+            User.update(settings=json.dumps(settings)).where(
+                User.id == user.id
+            ).execute()
 
 
 def rollback(migrator: Migrator, database: pw.Database, *, fake=False):
     """Decrypt user valves back to plaintext."""
     from open_webui.utils.valve_encryption import decrypt_user_valves
 
-    cursor = database.execute_sql('SELECT "id", "settings" FROM "user" WHERE "settings" IS NOT NULL')
+    User = migrator.orm["user"]
 
-    for user_id, settings_raw in cursor.fetchall():
+    for user in User.select().where(User.settings.is_null(False)):
+        settings_raw = user.settings
         if not settings_raw:
             continue
 
-        settings = (
-            json.loads(settings_raw)
-            if isinstance(settings_raw, str)
-            else settings_raw
-        )
+        try:
+            settings = (
+                json.loads(settings_raw)
+                if isinstance(settings_raw, str)
+                else settings_raw
+            )
+        except (json.JSONDecodeError, TypeError):
+            log.warning("Rollback skipping user %s: malformed settings JSON", user.id)
+            continue
+
+        if not isinstance(settings, dict):
+            log.warning("Rollback skipping user %s: settings is not a dict", user.id)
+            continue
 
         changed = False
 
@@ -107,10 +127,12 @@ def rollback(migrator: Migrator, database: pw.Database, *, fake=False):
                         )
                         changed = True
                     except Exception:
-                        pass
+                        log.warning(
+                            "Rollback failed to decrypt valve %s/%s for user %s",
+                            category, valve_id, user.id,
+                        )
 
         if changed:
-            database.execute_sql(
-                'UPDATE "user" SET "settings" = %s WHERE "id" = %s',
-                (json.dumps(settings), user_id),
-            )
+            User.update(settings=json.dumps(settings)).where(
+                User.id == user.id
+            ).execute()
diff --git a/backend/open_webui/utils/valve_encryption.py b/backend/open_webui/utils/valve_encryption.py
index 28a856d45c..45389d5881 100644
--- a/backend/open_webui/utils/valve_encryption.py
+++ b/backend/open_webui/utils/valve_encryption.py
@@ -3,23 +3,32 @@ import hashlib
 import json
 import logging
 
-from cryptography.fernet import Fernet
+from cryptography.fernet import Fernet, InvalidToken
 
 from open_webui.env import WEBUI_SECRET_KEY
 
 log = logging.getLogger(__name__)
 
+_DEFAULT_SECRET = "t0p-s3cr3t"
+
 
 def _make_fernet(key: str) -> Fernet:
     """Derive a Fernet instance from an arbitrary string key."""
-    if len(key) != 44:
+    try:
+        return Fernet(key.encode())
+    except Exception:
         key_bytes = hashlib.sha256(key.encode()).digest()
-        key_encoded = base64.urlsafe_b64encode(key_bytes)
-    else:
-        key_encoded = key.encode()
-    return Fernet(key_encoded)
+        return Fernet(base64.urlsafe_b64encode(key_bytes))
 
 
+if WEBUI_SECRET_KEY == _DEFAULT_SECRET:
+    log.warning(
+        "WEBUI_SECRET_KEY is set to the default value '%s'. "
+        "Encrypted valve data is trivially decryptable. "
+        "Set a strong, unique WEBUI_SECRET_KEY in production.",
+        _DEFAULT_SECRET,
+    )
+
 _fernet = _make_fernet(WEBUI_SECRET_KEY)
 
 
@@ -37,7 +46,19 @@ def decrypt_user_valves(stored) -> dict:
         try:
             decrypted = _fernet.decrypt(stored.encode()).decode()
             return json.loads(decrypted)
+        except InvalidToken:
+            log.error(
+                "Failed to decrypt user valves: key mismatch or corrupted data. "
+                "Returning empty valves. The original encrypted value is preserved in the database."
+            )
+            return {}
+        except json.JSONDecodeError:
+            log.error(
+                "Decrypted user valves but got malformed JSON. "
+                "Returning empty valves. The original encrypted value is preserved in the database."
+            )
+            return {}
         except Exception as e:
-            log.error(f"Error decrypting user valves: {type(e).__name__}: {e}")
-            raise
+            log.error("Unexpected error decrypting user valves: %s: %s", type(e).__name__, e)
+            return {}
     return {}