diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index fcd72ba..529a80b 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -1295,6 +1295,57 @@
 }
 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
 
+#if defined(MBEDTLS_SSL_CID)
+static int ssl_parse_cid_ext( mbedtls_ssl_context *ssl,
+                              const unsigned char *buf,
+                              size_t len )
+{
+    size_t peer_cid_len;
+
+    if( /* CID extension only makes sense in DTLS */
+        ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ||
+        /* The server must only send the CID extension if we have offered it. */
+        ssl->negotiate_cid == MBEDTLS_SSL_CID_DISABLED ||
+        /* CID extension must at least contain the length byte */
+        len < 1 )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching CID extension" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
+        return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+    }
+
+    peer_cid_len = *buf++;
+    len--;
+
+    if( peer_cid_len > MBEDTLS_SSL_CID_OUT_LEN_MAX )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching CID extension" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
+        return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+    }
+
+    if( len != peer_cid_len )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching CID extension" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
+        return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+    }
+
+    ssl->handshake->peer_cid_len = (uint8_t) peer_cid_len;
+    memcpy( ssl->handshake->peer_cid, buf, peer_cid_len );
+
+    MBEDTLS_SSL_DEBUG_MSG( 3, ( "Use of CID extension negotiated" ) );
+    MBEDTLS_SSL_DEBUG_BUF( 3, "Server CID", buf, peer_cid_len );
+
+    ssl->handshake->cid_in_use = MBEDTLS_SSL_CID_ENABLED;
+
+    return( 0 );
+}
+#endif /* MBEDTLS_SSL_CID */
+
 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
 static int ssl_parse_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
                                          const unsigned char *buf,
@@ -1946,6 +1997,20 @@
             break;
 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
 
+#if defined(MBEDTLS_SSL_CID)
+        case MBEDTLS_TLS_EXT_CID:
+            MBEDTLS_SSL_DEBUG_MSG( 3, ( "found CID extension" ) );
+
+            if( ( ret = ssl_parse_cid_ext( ssl,
+                                           ext + 4,
+                                           ext_size ) ) != 0 )
+            {
+                return( ret );
+            }
+
+            break;
+#endif /* MBEDTLS_SSL_CID */
+
 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
         case MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC:
             MBEDTLS_SSL_DEBUG_MSG( 3, ( "found encrypt_then_mac extension" ) );