diff --git a/cmd/nerdctl/login.go b/cmd/nerdctl/login.go
index 07e03253f50..8648efdedff 100644
--- a/cmd/nerdctl/login.go
+++ b/cmd/nerdctl/login.go
@@ -19,6 +19,7 @@ package main
 import (
 	"errors"
 	"io"
+	"net/url"
 	"strings"
 
 	"github.com/containerd/log"
@@ -82,6 +83,11 @@ func processLoginOptions(cmd *cobra.Command) (types.LoginCommandOptions, error)
 		password = strings.TrimSuffix(string(contents), "\n")
 		password = strings.TrimSuffix(password, "\r")
 	}
+
+	if strings.Contains(username, ":") {
+		return types.LoginCommandOptions{}, errors.New("username cannot contain colons")
+	}
+
 	return types.LoginCommandOptions{
 		GOptions: globalOptions,
 		Username: username,