diff --git a/locales/en.json b/locales/en.json
index 18ab84be1..694df0707 100644
--- a/locales/en.json
+++ b/locales/en.json
@@ -4,6 +4,7 @@
     "admin_password": "Administration password",
     "admin_password_change_failed": "Unable to change password",
     "admin_password_changed": "The administration password has been changed",
+    "admin_password_too_long": "Please choose a password shorter than 127 characters",
     "app_already_installed": "{app:s} is already installed",
     "app_already_installed_cant_change_url": "This app is already installed. The url cannot be changed just by this function. Look into `app changeurl` if it's available.",
     "app_already_up_to_date": "{app:s} is already up to date",
diff --git a/src/yunohost/tools.py b/src/yunohost/tools.py
index a011b1546..42114c7e9 100644
--- a/src/yunohost/tools.py
+++ b/src/yunohost/tools.py
@@ -132,6 +132,11 @@ def tools_adminpw(auth, new_password, check_strength=True):
     if check_strength:
         assert_password_is_strong_enough("admin", new_password)
 
+    # UNIX seems to not like password longer than 127 chars ...
+    # e.g. SSH login gets broken (or even 'su admin' when entering the password)
+    if len(new_password) >= 127:
+        raise YunohostError('admin_password_too_long')
+
     new_hash = _hash_user_password(new_password)
 
     try: