diff --git a/proxy/cache.go b/proxy/cache.go
index a998e9771..13f739931 100644
--- a/proxy/cache.go
+++ b/proxy/cache.go
@@ -104,7 +104,7 @@ func (c *cache) unpackItem(data []byte, req *dns.Msg) (ci *cacheItem, expired bo
 		ttl = uint32(expire - now)
 	}
 
-	l := int(binary.BigEndian.Uint32(b.Next(packedMsgLenSz)))
+	l := int(binary.BigEndian.Uint16(b.Next(packedMsgLenSz)))
 	if l == 0 {
 		return nil, expired
 	}