diff --git a/plinth/__main__.py b/plinth/__main__.py
index 8fb8c3d3a..6b9908040 100644
--- a/plinth/__main__.py
+++ b/plinth/__main__.py
@@ -245,6 +245,7 @@ def configure_django():
                 {'BACKEND': 'django.core.cache.backends.dummy.DummyCache'}},
         CAPTCHA_FONT_PATH=['/usr/share/fonts/truetype/ttf-bitstream-vera/Vera.ttf'],
         CAPTCHA_LENGTH=6,
+        CAPTCHA_FLITE_PATH='/usr/bin/flite',
         DATABASES={'default':
                    {'ENGINE': 'django.db.backends.sqlite3',
                     'NAME': cfg.store_file}},
diff --git a/plinth/modules/sso/__init__.py b/plinth/modules/sso/__init__.py
index 48e70b448..50c6a4bab 100644
--- a/plinth/modules/sso/__init__.py
+++ b/plinth/modules/sso/__init__.py
@@ -29,7 +29,7 @@ depends = ['security', 'apache']
 
 name = _('Single Sign On')
 
-managed_packages = ['libapache2-mod-auth-pubtkt', 'openssl', 'python3-openssl']
+managed_packages = ['libapache2-mod-auth-pubtkt', 'openssl', 'python3-openssl', 'flite']
 
 
 def setup(helper, old_version=None):