diff --git a/amqtt/codecs_amqtt.py b/amqtt/codecs_amqtt.py
index f385155..3e425a3 100644
--- a/amqtt/codecs_amqtt.py
+++ b/amqtt/codecs_amqtt.py
@@ -2,7 +2,7 @@ import asyncio
 from struct import pack, unpack
 
 from amqtt.adapters import ReaderAdapter
-from amqtt.errors import NoDataError
+from amqtt.errors import NoDataError, ZeroLengthReadError
 
 
 def bytes_to_hex_str(data: bytes | bytearray) -> str:
@@ -59,7 +59,7 @@ async def read_or_raise(reader: ReaderAdapter | asyncio.StreamReader, n: int = -
         data = await reader.read(n)
     except (asyncio.IncompleteReadError, ConnectionResetError, BrokenPipeError):
         data = None
-    if not data:
+    if data is None:
         msg = "No more data"
         raise NoDataError(msg)
     return data
@@ -72,6 +72,8 @@ async def decode_string(reader: ReaderAdapter | asyncio.StreamReader) -> str:
     :return: string read from stream.
     """
     length_bytes = await read_or_raise(reader, 2)
+    if len(length_bytes) < 1:
+        raise ZeroLengthReadError
     str_length = unpack("!H", length_bytes)[0]
     if str_length:
         byte_str = await read_or_raise(reader, str_length)
@@ -90,6 +92,8 @@ async def decode_data_with_length(reader: ReaderAdapter | asyncio.StreamReader)
     :return: bytes read from stream (without length).
     """
     length_bytes = await read_or_raise(reader, 2)
+    if len(length_bytes) < 1:
+        raise ZeroLengthReadError
     bytes_length = unpack("!H", length_bytes)[0]
     return await read_or_raise(reader, bytes_length)
 
diff --git a/amqtt/errors.py b/amqtt/errors.py
index 71d65c7..ca6cafc 100644
--- a/amqtt/errors.py
+++ b/amqtt/errors.py
@@ -13,6 +13,9 @@ class CodecError(Exception):
 class NoDataError(Exception):
     """Exceptions thrown by packet encode/decode functions."""
 
+class ZeroLengthReadError(NoDataError):
+    def __init__(self) -> None:
+        super().__init__("Decoding a string of length zero.")
 
 class BrokerError(Exception):
     """Exceptions thrown by broker."""