diff --git a/CHANGELOG.md b/CHANGELOG.md
index 53d76d40..c6143e09 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ All notable changes to this project will be documented in this file. The format
 
 ### Fixed
 
+- **scripts**: Fix unbound variable error ([#2849](https://github.com/docker-mailserver/docker-mailserver/pull/2849))
 - **scripts**: Run `user-patches.sh` right before starting daemons ([#2817](https://github.com/docker-mailserver/docker-mailserver/pull/2817))
 - **scripts**: Run Amavis cron job only when Amavis is enabled ([#2831](https://github.com/docker-mailserver/docker-mailserver/pull/2831))
 
diff --git a/target/bin/setup b/target/bin/setup
index 8d2093fb..69232438 100755
--- a/target/bin/setup
+++ b/target/bin/setup
@@ -110,7 +110,7 @@ function _main
         ( del      ) shift 2 ; delmailuser "${@}" ;;
         ( restrict ) shift 2 ; restrict-access "${@}" ;;
         ( list     ) listmailuser ;;
-        ( *        ) _invalid_command "${1}" "${2}" ;;
+        ( *        ) _invalid_command "${1}" "${2:-}" ;;
       esac
       ;;
 
@@ -119,7 +119,7 @@ function _main
         ( add      ) shift 2 ; addalias "${1}" "${2}" ;;
         ( del      ) shift 2 ; delalias "${1}" "${2}" ;;
         ( list     ) shift 2 ; listalias ;;
-        ( *        ) _invalid_command "${1}" "${2}" ;;
+        ( *        ) _invalid_command "${1}" "${2:-}" ;;
       esac
       ;;
 
@@ -127,7 +127,7 @@ function _main
       case ${2:-} in
         ( set      ) shift 2 ; setquota "${@}" ;;
         ( del      ) shift 2 ; delquota "${@}" ;;
-        ( *        ) _invalid_command "${1}" "${2}" ;;
+        ( *        ) _invalid_command "${1}" "${2:-}" ;;
       esac
       ;;
 
@@ -137,14 +137,14 @@ function _main
         ( update   ) shift 2 ; updatedovecotmasteruser "${@}" ;;
         ( del      ) shift 2 ; deldovecotmasteruser "${@}" ;;
         ( list     ) listdovecotmasteruser ;;
-        ( *        ) _invalid_command "${1}" "${2}" ;;
+        ( *        ) _invalid_command "${1}" "${2:-}" ;;
       esac
       ;;
 
     ( config )
       case ${2:-} in
         ( dkim     ) shift 2 ; open-dkim "${@}" ;;
-        ( *        ) _invalid_command "${1}" "${2}" ;;
+        ( *        ) _invalid_command "${1}" "${2:-}" ;;
       esac
       ;;
 
@@ -153,7 +153,7 @@ function _main
         ( add-domain     ) shift 2 ; addrelayhost "${@}" ;;
         ( add-auth       ) shift 2 ; addsaslpassword "${@}" ;;
         ( exclude-domain ) shift 2 ; excluderelaydomain "${@}" ;;
-        ( *              ) _invalid_command "${1}" "${2}" ;;
+        ( *              ) _invalid_command "${1}" "${2:-}" ;;
       esac
       ;;