diff --git a/components/engine/builder/dockerfile/shell/envVarTest b/components/engine/builder/dockerfile/shell/envVarTest
index 946b278592..677b33d9a7 100644
--- a/components/engine/builder/dockerfile/shell/envVarTest
+++ b/components/engine/builder/dockerfile/shell/envVarTest
@@ -119,3 +119,14 @@ A|안녕${XXX:-\$PWD:}xx       |     안녕$PWD:xx
 A|안녕${XXX:-\${PWD}z}xx     |     안녕${PWDz}xx
 A|$KOREAN                    |     한국어
 A|안녕$KOREAN                |     안녕한국어
+A|${{aaa}                   |     error
+A|${aaa}}                   |     }
+A|${aaa                     |     error
+A|${{aaa:-bbb}              |     error
+A|${aaa:-bbb}}              |     bbb}
+A|${aaa:-bbb                |     error
+A|${aaa:-bbb}               |     bbb
+A|${aaa:-${bbb:-ccc}}       |     ccc
+A|${aaa:-bbb ${foo}         |     error
+A|${aaa:-bbb {foo}          |     bbb {foo
+
diff --git a/components/engine/builder/dockerfile/shell/lex.go b/components/engine/builder/dockerfile/shell/lex.go
index bd3fac525a..d0d6f53e66 100644
--- a/components/engine/builder/dockerfile/shell/lex.go
+++ b/components/engine/builder/dockerfile/shell/lex.go
@@ -131,7 +131,7 @@ func (sw *shellWord) processStopOn(stopChar rune) (string, []string, error) {
 
 		if stopChar != scanner.EOF && ch == stopChar {
 			sw.scanner.Next()
-			break
+			return result.String(), words.getWords(), nil
 		}
 		if fn, ok := charFuncMapping[ch]; ok {
 			// Call special processing func for certain chars
@@ -166,7 +166,9 @@ func (sw *shellWord) processStopOn(stopChar rune) (string, []string, error) {
 			result.WriteRune(ch)
 		}
 	}
-
+	if stopChar != scanner.EOF {
+		return "", []string{}, errors.Errorf("unexpected end of statement while looking for matching %s", string(stopChar))
+	}
 	return result.String(), words.getWords(), nil
 }
 
@@ -261,12 +263,17 @@ func (sw *shellWord) processDollar() (string, error) {
 	sw.scanner.Next()
 	name := sw.processName()
 	ch := sw.scanner.Peek()
-	if ch == '}' {
+	switch ch {
+	case '}':
 		// Normal ${xx} case
 		sw.scanner.Next()
 		return sw.getEnv(name), nil
-	}
-	if ch == ':' {
+	case '{':
+		// Invalid ${{xx} case
+		return "", errors.New("syntax error: bad substitution")
+	case scanner.EOF:
+		return "", errors.New("syntax error: missing '}'")
+	case ':':
 		// Special ${xx:...} format processing
 		// Yes it allows for recursive $'s in the ... spot
 
@@ -275,6 +282,9 @@ func (sw *shellWord) processDollar() (string, error) {
 
 		word, _, err := sw.processStopOn('}')
 		if err != nil {
+			if sw.scanner.Peek() == scanner.EOF {
+				return "", errors.New("syntax error: missing '}'")
+			}
 			return "", err
 		}
 
diff --git a/components/engine/builder/dockerfile/shell/lex_test.go b/components/engine/builder/dockerfile/shell/lex_test.go
index f38da2026f..765ae14b25 100644
--- a/components/engine/builder/dockerfile/shell/lex_test.go
+++ b/components/engine/builder/dockerfile/shell/lex_test.go
@@ -53,7 +53,7 @@ func TestShellParser4EnvVars(t *testing.T) {
 			((platform == "U" || platform == "A") && runtime.GOOS != "windows") {
 			newWord, err := shlex.ProcessWord(source, envs)
 			if expected == "error" {
-				assert.Check(t, is.ErrorContains(err, ""))
+				assert.Check(t, is.ErrorContains(err, ""), "input: %q, result: %q", source, newWord)
 			} else {
 				assert.Check(t, err)
 				assert.Check(t, is.Equal(newWord, expected))