diff --git a/pkg/vm/vm.go b/pkg/vm/vm.go
index 3592291a9..a523642d5 100644
--- a/pkg/vm/vm.go
+++ b/pkg/vm/vm.go
@@ -318,18 +318,22 @@ func (v *VM) execute(ctx *Context, op Instruction) {
 		v.estack.PushVal(ab)
 	case SUBSTR:
 		l := int(v.estack.Pop().BigInt().Int64())
-		o := int(v.estack.Pop().BigInt().Int64())
-		s := v.estack.Pop().Bytes()
 		if l < 0 {
 			panic("negative length")
 		}
+		o := int(v.estack.Pop().BigInt().Int64())
 		if o < 0 {
 			panic("negative index")
 		}
-		if l+o > len(s) {
-			panic("out of bounds access")
+		s := v.estack.Pop().Bytes()
+		if o > len(s) {
+			panic("invalid offset")
 		}
-		v.estack.PushVal(s[o : o+l])
+		last := l + o
+		if last > len(s) {
+			last = len(s)
+		}
+		v.estack.PushVal(s[o:last])
 	case LEFT:
 		l := int(v.estack.Pop().BigInt().Int64())
 		if l < 0 {
diff --git a/pkg/vm/vm_test.go b/pkg/vm/vm_test.go
index 9d8e1ca0f..3856d9d2a 100644
--- a/pkg/vm/vm_test.go
+++ b/pkg/vm/vm_test.go
@@ -1138,20 +1138,22 @@ func TestSUBSTRBadOffset(t *testing.T) {
 	prog := makeProgram(SUBSTR)
 	vm := load(prog)
 	vm.estack.PushVal([]byte("abcdef"))
-	vm.estack.PushVal(6)
+	vm.estack.PushVal(7)
 	vm.estack.PushVal(1)
 	vm.Run()
 	assert.Equal(t, true, vm.state.HasFlag(faultState))
 }
 
-func TestSUBSTRBadLen(t *testing.T) {
+func TestSUBSTRBigLen(t *testing.T) {
 	prog := makeProgram(SUBSTR)
 	vm := load(prog)
 	vm.estack.PushVal([]byte("abcdef"))
 	vm.estack.PushVal(1)
 	vm.estack.PushVal(6)
 	vm.Run()
-	assert.Equal(t, true, vm.state.HasFlag(faultState))
+	assert.Equal(t, false, vm.state.HasFlag(faultState))
+	assert.Equal(t, 1, vm.estack.Len())
+	assert.Equal(t, []byte("bcdef"), vm.estack.Pop().Bytes())
 }
 
 func TestSUBSTRBad387(t *testing.T) {
@@ -1163,7 +1165,9 @@ func TestSUBSTRBad387(t *testing.T) {
 	vm.estack.PushVal(1)
 	vm.estack.PushVal(6)
 	vm.Run()
-	assert.Equal(t, true, vm.state.HasFlag(faultState))
+	assert.Equal(t, false, vm.state.HasFlag(faultState))
+	assert.Equal(t, 1, vm.estack.Len())
+	assert.Equal(t, []byte("bcdef"), vm.estack.Pop().Bytes())
 }
 
 func TestSUBSTRBadNegativeOffset(t *testing.T) {