diff --git a/frontend/dockerfile/dockerfile2llb/convert.go b/frontend/dockerfile/dockerfile2llb/convert.go
index 00e92b3f..cc76b2be 100644
--- a/frontend/dockerfile/dockerfile2llb/convert.go
+++ b/frontend/dockerfile/dockerfile2llb/convert.go
@@ -100,6 +100,9 @@ func Dockerfile2LLB(ctx context.Context, dt []byte, opt ConvertOpt) (*llb.State,
 		if err != nil {
 			return nil, nil, err
 		}
+		if name == "" {
+			return nil, nil, errors.Errorf("base name (%s) should not be blank", st.BaseName)
+		}
 		st.BaseName = name
 
 		ds := &dispatchState{
diff --git a/frontend/dockerfile/dockerfile2llb/convert_test.go b/frontend/dockerfile/dockerfile2llb/convert_test.go
index c21c61de..ee7dc0f6 100644
--- a/frontend/dockerfile/dockerfile2llb/convert_test.go
+++ b/frontend/dockerfile/dockerfile2llb/convert_test.go
@@ -41,4 +41,12 @@ COPY --from=0 f2 /
 		Target: "nosuch",
 	})
 	assert.Error(t, err)
+
+	df = `FROM "" AS foo`
+	_, _, err = Dockerfile2LLB(appcontext.Context(), []byte(df), ConvertOpt{})
+	assert.Error(t, err)
+
+	df = `FROM ${BLANK} AS foo`
+	_, _, err = Dockerfile2LLB(appcontext.Context(), []byte(df), ConvertOpt{})
+	assert.Error(t, err)
 }