diff --git a/providers/fab/src/airflow/providers/fab/auth_manager/security_manager/override.py b/providers/fab/src/airflow/providers/fab/auth_manager/security_manager/override.py
index 2a74e680b9151..db260f7e9cfdd 100644
--- a/providers/fab/src/airflow/providers/fab/auth_manager/security_manager/override.py
+++ b/providers/fab/src/airflow/providers/fab/auth_manager/security_manager/override.py
@@ -62,7 +62,7 @@
 from flask_jwt_extended import JWTManager
 from flask_login import LoginManager
 from itsdangerous import want_bytes
-from markupsafe import Markup
+from markupsafe import Markup, escape
 from sqlalchemy import func, inspect, or_, select
 from sqlalchemy.exc import MultipleResultsFound
 from sqlalchemy.orm import joinedload
@@ -547,8 +547,9 @@ def reset_user_sessions(self, user: User) -> None:
             user_session_model = interface.sql_session_model
             num_sessions = session.query(user_session_model).count()
             if num_sessions > MAX_NUM_DATABASE_USER_SESSIONS:
+                safe_username = escape(user.username)
                 self._cli_safe_flash(
-                    f"The old sessions for user {user.username} have <b>NOT</b> been deleted!<br>"
+                    f"The old sessions for user {safe_username} have <b>NOT</b> been deleted!<br>"
                     f"You have a lot ({num_sessions}) of user sessions in the 'SESSIONS' table in "
                     f"your database.<br> "
                     "This indicates that this deployment might have an automated API calls that create "
@@ -565,9 +566,10 @@ def reset_user_sessions(self, user: User) -> None:
                         session.delete(s)
                 session.commit()
         else:
+            safe_username = escape(user.username)
             self._cli_safe_flash(
                 "Since you are using `securecookie` session backend mechanism, we cannot prevent "
-                f"some old sessions for user {user.username} to be reused.<br> If you want to make sure "
+                f"some old sessions for user {safe_username} to be reused.<br> If you want to make sure "
                 "that the user is logged out from all sessions, you should consider using "
                 "`database` session backend mechanism.<br> You can also change the 'secret_key` "
                 "webserver configuration for all your webserver instances and restart the webserver. "