diff --git a/chunks/chunks_test.go b/chunks/chunks_test.go
new file mode 100644
index 000000000..e153029b7
--- /dev/null
+++ b/chunks/chunks_test.go
@@ -0,0 +1,28 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package chunks
+
+import (
+	"testing"
+
+	"github.com/prometheus/tsdb/testutil"
+)
+
+func TestReaderWithInvalidBuffer(t *testing.T) {
+	b := realByteSlice([]byte{0x81, 0x81, 0x81, 0x81, 0x81, 0x81})
+	r := &Reader{bs: []ByteSlice{b}}
+
+	_, err := r.Chunk(0)
+	testutil.NotOk(t, err)
+}
diff --git a/index/index_test.go b/index/index_test.go
index f1b4d4181..8d7198136 100644
--- a/index/index_test.go
+++ b/index/index_test.go
@@ -380,3 +380,11 @@ func TestPersistence_index_e2e(t *testing.T) {
 
 	testutil.Ok(t, ir.Close())
 }
+
+func TestReaderWithInvalidBuffer(t *testing.T) {
+	b := realByteSlice([]byte{0x81, 0x81, 0x81, 0x81, 0x81, 0x81})
+	r := &Reader{b: b}
+
+	db := r.decbufUvarintAt(0)
+	testutil.NotOk(t, db.err())
+}