diff --git a/daemon/handlers/auth.py b/daemon/handlers/auth.py
index 6bdf796..b68dc19 100644
--- a/daemon/handlers/auth.py
+++ b/daemon/handlers/auth.py
@@ -135,7 +135,7 @@ def auth_logout(request: Any, body: Any) -> dict[str, Any]:
         Success response.
     """
     if not body:
-        return {}
+        raise ValueError("Request body is required")
 
     jti = body.get("jti")
     if jti:
diff --git a/lib/auth_users.py b/lib/auth_users.py
index b6a3abe..f53e9e6 100644
--- a/lib/auth_users.py
+++ b/lib/auth_users.py
@@ -19,9 +19,9 @@ from lib.db import (
     Q_DELETE_PERMISSIONS,
     Q_DELETE_USER,
     Q_INSERT_USER,
-    Q_SELECT_ALL_USERS,
     Q_SELECT_PERMISSIONS,
     Q_SELECT_USER_BY_NAME,
+    Q_SELECT_USERS_WITH_PERMS,
     Q_UPDATE_PASSWORD,
     Q_UPSERT_PERMISSION,
     get_db,
@@ -244,21 +244,22 @@ def list_users() -> list[dict[str, Any]]:
         List of user summary dicts.
     """
     db = get_db()
-    rows = db.query(Q_SELECT_ALL_USERS, ())
+    rows = db.query(Q_SELECT_USERS_WITH_PERMS, ())
 
-    result = []
+    users: dict[int, dict[str, Any]] = {}
     for row in rows:
-        username = row["username"]
-        permissions = _get_permissions(username)
-        result.append(
-            {
-                "id": row["id"],
-                "username": username,
-                "permissions": permissions,
+        uid = row["id"]
+        if uid not in users:
+            users[uid] = {
+                "id": uid,
+                "username": row["username"],
+                "permissions": {},
                 "created_at": row["created_at"],
             }
-        )
-    return result
+        if row["subsystem"] is not None:
+            users[uid]["permissions"][row["subsystem"]] = row["level"]
+
+    return list(users.values())
 
 
 def delete_user(username: str) -> bool:
diff --git a/lib/db.py b/lib/db.py
index 791f6db..09bfea2 100644
--- a/lib/db.py
+++ b/lib/db.py
@@ -53,6 +53,7 @@ Q_SELECT_WEBAUTHN_COUNTS = "select_webauthn_counts"
 Q_DELETE_WEBAUTHN = "delete_webauthn"
 Q_UPDATE_WEBAUTHN_SIGN_COUNT = "update_webauthn_sign_count"
 Q_SELECT_ALL_USERS = "select_all_users"
+Q_SELECT_USERS_WITH_PERMS = "select_users_with_perms"
 Q_SELECT_USER_JWT_SECRET = "select_user_jwt_secret"
 Q_UPDATE_JWT_SECRET = "update_jwt_secret"
 
diff --git a/lib/db_sqlite.py b/lib/db_sqlite.py
index f99f80a..24fc66f 100644
--- a/lib/db_sqlite.py
+++ b/lib/db_sqlite.py
@@ -27,6 +27,7 @@ from lib.db import (
     Q_SELECT_USER_BY_ID,
     Q_SELECT_USER_BY_NAME,
     Q_SELECT_USER_JWT_SECRET,
+    Q_SELECT_USERS_WITH_PERMS,
     Q_SELECT_WEBAUTHN_COUNTS,
     Q_SELECT_WEBAUTHN_ID,
     Q_SELECT_WEBAUTHN_USER,
@@ -70,6 +71,11 @@ class SQLiteBackend(Database):
         Q_SELECT_ALL_USERS: (
             "SELECT id, username, created_at FROM users ORDER BY username"
         ),
+        Q_SELECT_USERS_WITH_PERMS: (
+            "SELECT u.id, u.username, u.created_at, p.subsystem, p.level "
+            "FROM users u LEFT JOIN permissions p ON u.username = p.username "
+            "ORDER BY u.username"
+        ),
         Q_SELECT_USER_JWT_SECRET: ("SELECT jwt_secret FROM users WHERE username = ?"),
         Q_UPDATE_JWT_SECRET: ("UPDATE users SET jwt_secret = ? WHERE username = ?"),
         # Permissions
diff --git a/lib/webauthn.py b/lib/webauthn.py
index aec6141..458a1a0 100644
--- a/lib/webauthn.py
+++ b/lib/webauthn.py
@@ -324,6 +324,9 @@ def verify_authentication(
         raise ValueError("Credential not found")
 
     cred_row = cred_rows[0]
+    if cred_row["username"] != username:
+        raise ValueError("Credential not found")
+
     public_key = b64u_decode(cred_row["public_key"])
     old_sign_count = cred_row["sign_count"]