diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 70820be..70dd4be2 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -3010,6 +3010,14 @@
  */
 //#define MBEDTLS_SSL_OUT_CONTENT_LEN             16384
 
+/** \def MBEDTLS_SSL_DTLS_MAX_BUFFERING
+ *
+ * Maximum number of heap-allocated bytes for the purpose of
+ * DTLS handshake message reassembly and future message buffering.
+ *
+ */
+//#define MBEDTLS_SSL_DTLS_MAX_BUFFERING             ( 2 * 16384 )
+
 //#define MBEDTLS_SSL_DEFAULT_TICKET_LIFETIME     86400 /**< Lifetime of session tickets (if enabled) */
 //#define MBEDTLS_PSK_MAX_LEN               32 /**< Max size of TLS pre-shared keys, in bytes (default 256 bits) */
 //#define MBEDTLS_SSL_COOKIE_TIMEOUT        60 /**< Default expiration delay of DTLS cookies, in seconds if HAVE_TIME, or in number of cookies issued */
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 3a8dd21..29c139e 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -243,6 +243,10 @@
 #define MBEDTLS_SSL_OUT_CONTENT_LEN MBEDTLS_SSL_MAX_CONTENT_LEN
 #endif
 
+#if !defined(MBEDTLS_SSL_DTLS_MAX_BUFFERING)
+#define MBEDTLS_SSL_DTLS_MAX_BUFFERING ( 2 * MBEDTLS_SSL_IN_CONTENT_LEN )
+#endif
+
 /* \} name SECTION: Module settings */
 
 /*
diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index bfc3a5a..2c0684f 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -311,6 +311,9 @@
 
     struct
     {
+        size_t total_bytes_buffered; /*!< Cumulative size of heap allocated
+                                      *   buffers used for message buffering. */
+
         uint8_t seen_ccs;               /*!< Indicates if a CCS message has
                                          *   been seen in the current flight. */
 
@@ -320,6 +323,7 @@
             uint8_t is_fragmented : 1;
             uint8_t is_complete   : 1;
             unsigned char *data;
+            size_t data_len;
         } hs[MBEDTLS_SSL_MAX_BUFFERED_HS];
 
         struct