diff --git a/CocoaMQTT.podspec b/CocoaMQTT.podspec
index e0124fa0..0d55c868 100644
--- a/CocoaMQTT.podspec
+++ b/CocoaMQTT.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name        = "CocoaMQTT"
-  s.version     = "2.1.0"
+  s.version     = "2.1.1"
   s.summary     = "MQTT v3.1.1 client library for iOS and OS X written with Swift 5"
   s.homepage    = "https://github.com/emqx/CocoaMQTT"
   s.license     = { :type => "MIT" }
@@ -12,7 +12,7 @@ Pod::Spec.new do |s|
   s.ios.deployment_target = "9.0"
   s.tvos.deployment_target = "10.0"
   # s.watchos.deployment_target = "2.0"
-  s.source   = { :git => "https://github.com/emqx/CocoaMQTT.git", :tag => "2.1.0"}
+  s.source   = { :git => "https://github.com/emqx/CocoaMQTT.git", :tag => "2.1.1"}
   s.default_subspec = 'Core'
   
   s.subspec 'Core' do |ss|
diff --git a/Source/CocoaMQTTReader.swift b/Source/CocoaMQTTReader.swift
index f5a00fca..239accd2 100644
--- a/Source/CocoaMQTTReader.swift
+++ b/Source/CocoaMQTTReader.swift
@@ -78,7 +78,11 @@ class CocoaMQTTReader {
             // more
         } else {
             let result = multiply.multipliedReportingOverflow(by: 128)
-            multiply = result.partialValue
+            if !result.overflow {
+                multiply = result.partialValue
+            }else{
+                reset()
+            }
             readLength()
         }
     }