diff --git a/roles/matrix-synapse/tasks/register_user.yml b/roles/matrix-synapse/tasks/register_user.yml
index da0e28c3..9c2a3ea0 100644
--- a/roles/matrix-synapse/tasks/register_user.yml
+++ b/roles/matrix-synapse/tasks/register_user.yml
@@ -28,4 +28,4 @@
   when: "start_result.changed"
 
 - name: Register user
-  shell: "{{ matrix_local_bin_path }}/matrix-synapse-register-user {{ username }} {{ password }} {{ '1' if admin == 'yes' else '0' }}"
+  command: "{{ matrix_local_bin_path }}/matrix-synapse-register-user {{ username|quote }} {{ password|quote }} {{ '1' if admin == 'yes' else '0' }}"
diff --git a/roles/matrix-synapse/tasks/update_user_password.yml b/roles/matrix-synapse/tasks/update_user_password.yml
index 0d77f5dd..1e86bd49 100644
--- a/roles/matrix-synapse/tasks/update_user_password.yml
+++ b/roles/matrix-synapse/tasks/update_user_password.yml
@@ -36,8 +36,8 @@
   when: "start_result.changed or postgres_start_result.changed"
 
 - name: Generate password hash
-  shell: "/usr/bin/docker exec matrix-synapse /usr/local/bin/hash_password -c /data/homeserver.yaml -p {{ password }}"
+  shell: "/usr/bin/docker exec matrix-synapse /usr/local/bin/hash_password -c /data/homeserver.yaml -p {{ password|quote }}"
   register: password_hash
 
 - name: Update user password hash
-  shell: "{{ matrix_local_bin_path }}/matrix-postgres-update-user-password-hash {{ username }} '{{ password_hash.stdout }}'"
+  command: "{{ matrix_local_bin_path }}/matrix-postgres-update-user-password-hash {{ username|quote }} {{ password_hash.stdout|quote }}"