diff --git a/core/io.go b/core/io.go
index fa6334ea..a9ba6acb 100644
--- a/core/io.go
+++ b/core/io.go
@@ -29,6 +29,9 @@ func ReadByte(r io.Reader) (byte, error) {
 
 func ReadUInt8(r io.Reader) (uint8, error) {
 	b, err := ReadBytes(1, r)
+	if len(b) == 0 {
+		return 0, err
+	}
 	return uint8(b[0]), err
 }