diff --git a/src/Microsoft.AspNetCore.Server.Kestrel/Http/SocketInput.cs b/src/Microsoft.AspNetCore.Server.Kestrel/Http/SocketInput.cs
index 1588e83011..40532e17b4 100644
--- a/src/Microsoft.AspNetCore.Server.Kestrel/Http/SocketInput.cs
+++ b/src/Microsoft.AspNetCore.Server.Kestrel/Http/SocketInput.cs
@@ -105,7 +105,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Http
                     }
                     else
                     {
-                        _tail.Next = _pinned;
+                        Volatile.Write(ref _tail.Next, _pinned);
                         _tail = _pinned;
                     }
 
diff --git a/src/Microsoft.AspNetCore.Server.Kestrel/Infrastructure/MemoryPoolBlock.cs b/src/Microsoft.AspNetCore.Server.Kestrel/Infrastructure/MemoryPoolBlock.cs
index 3badd57fce..a57332a839 100644
--- a/src/Microsoft.AspNetCore.Server.Kestrel/Infrastructure/MemoryPoolBlock.cs
+++ b/src/Microsoft.AspNetCore.Server.Kestrel/Infrastructure/MemoryPoolBlock.cs
@@ -55,14 +55,14 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
         /// the Start is guaranteed to be equal to Array.Offset. The value of Start may be assigned anywhere between Data.Offset and
         /// Data.Offset + Data.Count, and must be equal to or less than End.
         /// </summary>
-        public int Start { get; set; }
+        public int Start;
 
         /// <summary>
         /// The End represents the offset into Array where the range of "active" bytes ends. At the point when the block is leased
         /// the End is guaranteed to be equal to Array.Offset. The value of Start may be assigned anywhere between Data.Offset and
         /// Data.Offset + Data.Count, and must be equal to or less than End.
         /// </summary>
-        public int End { get; set; }
+        public volatile int End;
 
         /// <summary>
         /// Reference to the next block of data when the overall "active" bytes spans multiple blocks. At the point when the block is
@@ -70,7 +70,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
         /// working memory. The "active" memory is grown when bytes are copied in, End is increased, and Next is assigned. The "active" 
         /// memory is shrunk when bytes are consumed, Start is increased, and blocks are returned to the pool.
         /// </summary>
-        public MemoryPoolBlock Next { get; set; }
+        public MemoryPoolBlock Next;
 
         ~MemoryPoolBlock()
         {
diff --git a/src/Microsoft.AspNetCore.Server.Kestrel/Infrastructure/MemoryPoolIterator.cs b/src/Microsoft.AspNetCore.Server.Kestrel/Infrastructure/MemoryPoolIterator.cs
index 0fcfe7f434..3d42fba3b9 100644
--- a/src/Microsoft.AspNetCore.Server.Kestrel/Infrastructure/MemoryPoolIterator.cs
+++ b/src/Microsoft.AspNetCore.Server.Kestrel/Infrastructure/MemoryPoolIterator.cs
@@ -4,6 +4,7 @@
 using System;
 using System.Diagnostics;
 using System.Numerics;
+using System.Threading;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
 {
@@ -68,6 +69,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
             }
 
             var index = _index;
+            var wasLastBlock = block.Next == null;
 
             if (index < block.End)
             {
@@ -77,7 +79,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
 
             do
             {
-                if (block.Next == null)
+                if (wasLastBlock)
                 {
                     return -1;
                 }
@@ -87,6 +89,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
                     index = block.Start;
                 }
 
+                wasLastBlock = block.Next == null;
+
                 if (index < block.End)
                 {
                     _block = block;
@@ -102,7 +106,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
             {
                 return;
             }
+
+            var wasLastBlock = _block.Next == null;
             var following = _block.End - _index;
+
             if (following >= bytesToSkip)
             {
                 _index += bytesToSkip;
@@ -113,7 +120,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
             var index = _index;
             while (true)
             {
-                if (block.Next == null)
+                if (wasLastBlock)
                 {
                     return;
                 }
@@ -123,7 +130,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
                     block = block.Next;
                     index = block.Start;
                 }
+
+                wasLastBlock = block.Next == null;
                 following = block.End - index;
+
                 if (following >= bytesToSkip)
                 {
                     _block = block;
@@ -141,6 +151,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
                 return -1;
             }
 
+            var wasLastBlock = _block.Next == null;
             var index = _index;
 
             if (index < block.End)
@@ -150,7 +161,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
 
             do
             {
-                if (block.Next == null)
+                if (wasLastBlock)
                 {
                     return -1;
                 }
@@ -160,6 +171,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
                     index = block.Start;
                 }
 
+                wasLastBlock = block.Next == null;
+
                 if (index < block.End)
                 {
                     return block.Array[index];
@@ -173,11 +186,14 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
             {
                 return -1;
             }
-            else if (_block.End - _index >= sizeof(long))
+
+            var wasLastBlock = _block.Next == null;
+
+            if (_block.End - _index >= sizeof(long))
             {
                 return *(long*)(_block.DataFixedPtr + _index);
             }
-            else if (_block.Next == null)
+            else if (wasLastBlock)
             {
                 return -1;
             }
@@ -208,6 +224,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
 
             var block = _block;
             var index = _index;
+            var wasLastBlock = block.Next == null;
             var following = block.End - index;
             byte[] array;
             var byte0 = byte0Vector[0];
@@ -216,16 +233,16 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
             {
                 while (following == 0)
                 {
-                    var newBlock = block.Next;
-                    if (newBlock == null)
+                    if (wasLastBlock)
                     {
                         _block = block;
                         _index = index;
                         return -1;
                     }
-                    index = newBlock.Start;
-                    following = newBlock.End - index;
-                    block = newBlock;
+                    block = block.Next;
+                    index = block.Start;
+                    wasLastBlock = block.Next == null;
+                    following = block.End - index;
                 }
                 array = block.Array;
                 while (following > 0)
@@ -285,6 +302,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
 
             var block = _block;
             var index = _index;
+            var wasLastBlock = block.Next == null;
             var following = block.End - index;
             byte[] array;
             int byte0Index = int.MaxValue;
@@ -296,16 +314,16 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
             {
                 while (following == 0)
                 {
-                    var newBlock = block.Next;
-                    if (newBlock == null)
+                    if (wasLastBlock)
                     {
                         _block = block;
                         _index = index;
                         return -1;
                     }
-                    index = newBlock.Start;
-                    following = newBlock.End - index;
-                    block = newBlock;
+                    block = block.Next;
+                    index = block.Start;
+                    wasLastBlock = block.Next == null;
+                    following = block.End - index;
                 }
                 array = block.Array;
                 while (following > 0)
@@ -389,6 +407,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
 
             var block = _block;
             var index = _index;
+            var wasLastBlock = block.Next == null;
             var following = block.End - index;
             byte[] array;
             int byte0Index = int.MaxValue;
@@ -402,16 +421,16 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
             {
                 while (following == 0)
                 {
-                    var newBlock = block.Next;
-                    if (newBlock == null)
+                    if (wasLastBlock)
                     {
                         _block = block;
                         _index = index;
                         return -1;
                     }
-                    index = newBlock.Start;
-                    following = newBlock.End - index;
-                    block = newBlock;
+                    block = block.Next;
+                    index = block.Start;
+                    wasLastBlock = block.Next == null;
+                    following = block.End - index;
                 }
                 array = block.Array;
                 while (following > 0)
@@ -586,16 +605,13 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
             {
                 return false;
             }
-            else if (_index < _block.End)
-            {
-                _block.Array[_index++] = data;
-                return true;
-            }
 
             var block = _block;
             var index = _index;
             while (true)
             {
+                var wasLastBlock = block.Next == null;
+
                 if (index < block.End)
                 {
                     _block = block;
@@ -603,7 +619,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
                     block.Array[index] = data;
                     return true;
                 }
-                else if (block.Next == null)
+                else if (wasLastBlock)
                 {
                     return false;
                 }
@@ -660,6 +676,11 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
             var remaining = count;
             while (true)
             {
+                // Determine if we might attempt to copy data from block.Next before
+                // calculating "following" so we don't risk skipping data that could
+                // be added after block.End when we decide to copy from block.Next.
+                // block.End will always be advanced before block.Next is set.
+                var wasLastBlock = block.Next == null;
                 var following = block.End - index;
                 if (remaining <= following)
                 {
@@ -670,7 +691,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
                     }
                     return new MemoryPoolIterator(block, index + remaining);
                 }
-                else if (block.Next == null)
+                else if (wasLastBlock)
                 {
                     actual = count - remaining + following;
                     if (array != null)
@@ -728,7 +749,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
                 {
                     var nextBlock = pool.Lease();
                     block.End = blockIndex;
-                    block.Next = nextBlock;
+                    Volatile.Write(ref block.Next, nextBlock);
                     block = nextBlock;
 
                     blockIndex = block.Data.Offset;
@@ -781,7 +802,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Infrastructure
                     {
                         var nextBlock = pool.Lease();
                         block.End = blockIndex;
-                        block.Next = nextBlock;
+                        Volatile.Write(ref block.Next, nextBlock);
                         block = nextBlock;
 
                         blockIndex = block.Data.Offset;