diff --git a/components/gitpod-cli/cmd/preview.go b/components/gitpod-cli/cmd/preview.go
index 27c6026ae69391..32dcc9d9d15a76 100644
--- a/components/gitpod-cli/cmd/preview.go
+++ b/components/gitpod-cli/cmd/preview.go
@@ -19,7 +19,7 @@ import (
 	"github.com/gitpod-io/gitpod/gitpod-cli/pkg/theialib"
 )
 
-var regexLocalhost = regexp.MustCompile(`((^(localhost|127\.0\.0\.1))|(https?://(localhost|127\.0\.0\.1)))(:[0-9]+)?`)
+var regexLocalhost = regexp.MustCompile(`((^(localhost|127\.0\.0\.1))|(https?:\/\/(localhost|127\.0\.0\.1)))(:[0-9]+)?`)
 
 var previewCmdOpts struct {
 	External bool
diff --git a/components/ws-daemon/pkg/quota/size.go b/components/ws-daemon/pkg/quota/size.go
index d66895d9acd187..8216eda8035d5e 100644
--- a/components/ws-daemon/pkg/quota/size.go
+++ b/components/ws-daemon/pkg/quota/size.go
@@ -31,7 +31,7 @@ const (
 )
 
 var (
-	sizeRegexp = regexp.MustCompile(`(\d+)(k|m|g|t)?`)
+	sizeRegexp = regexp.MustCompile(`^(\d+)(k|m|g|t)?$`)
 
 	// ErrInvalidSize is returned by ParseSize if input was not a valid size
 	ErrInvalidSize = errors.New("invalid size")
diff --git a/components/ws-daemon/pkg/quota/size_test.go b/components/ws-daemon/pkg/quota/size_test.go
index cc21ae2579b1a2..68b3b822eb51cd 100644
--- a/components/ws-daemon/pkg/quota/size_test.go
+++ b/components/ws-daemon/pkg/quota/size_test.go
@@ -23,8 +23,8 @@ func TestParseSize(t *testing.T) {
 		{"42m", 42 * quota.Megabyte, nil},
 		{"42g", 42 * quota.Gigabyte, nil},
 		{"42t", 42 * quota.Terabyte, nil},
-		// This test should fail but doesn't because match somehow matches the regexp
-		// {"-42m", 0, quota.ErrInvalidSize},
+		{"-42m", 0, quota.ErrInvalidSize},
+		{"x42mx", 0, quota.ErrInvalidSize},
 		{"abc", 0, quota.ErrInvalidSize},
 		{"99999999999999999999999999999999999999999999999999999999999999999999999999999999", 0, quota.ErrInvalidSize},
 	}