diff --git a/AFNetworking/AFHTTPClient.m b/AFNetworking/AFHTTPClient.m
index 9673fa0..1626525 100644
--- a/AFNetworking/AFHTTPClient.m
+++ b/AFNetworking/AFHTTPClient.m
@@ -335,11 +335,17 @@ static void AFNetworkReachabilityReleaseCallback(const void *info) {}
     }
     
     self.networkReachability = SCNetworkReachabilityCreateWithName(kCFAllocatorDefault, [[self.baseURL host] UTF8String]);
-    
+
+    __weak AFHTTPClient *weakSelf = self;
     AFNetworkReachabilityStatusBlock callback = ^(AFNetworkReachabilityStatus status){
-        self.networkReachabilityStatus = status;
-        if (self.networkReachabilityStatusBlock) {
-            self.networkReachabilityStatusBlock(status);
+        __strong AFHTTPClient *strongSelf = weakSelf;
+        if (!strongSelf) {
+            // the weak ref is gone, depart this block
+            return;
+        }
+        strongSelf.networkReachabilityStatus = status;
+        if (strongSelf.networkReachabilityStatusBlock) {
+            strongSelf.networkReachabilityStatusBlock(status);
         }
     };