diff --git a/library/x509_crt.c b/library/x509_crt.c
index 5543522..99d3be2 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -893,7 +893,8 @@
 static int x509_get_crt_ext( unsigned char **p,
                              const unsigned char *end,
                              mbedtls_x509_crt *crt,
-                             mbedtls_x509_crt_ext_cb_t cb )
+                             mbedtls_x509_crt_ext_cb_t cb,
+                             void *p_ctx )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t len;
@@ -959,7 +960,7 @@
             /* Give the callback (if any) a chance to handle the extension */
             if( cb != NULL )
             {
-                ret = cb( crt, &extn_oid, is_critical, *p, end_ext_octet );
+                ret = cb( p_ctx, crt, &extn_oid, is_critical, *p, end_ext_octet );
                 if( ret != 0 )
                     return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
                 *p = end_ext_octet;
@@ -1073,7 +1074,8 @@
                                     const unsigned char *buf,
                                     size_t buflen,
                                     int make_copy,
-                                    mbedtls_x509_crt_ext_cb_t cb )
+                                    mbedtls_x509_crt_ext_cb_t cb,
+                                    void *p_ctx )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t len;
@@ -1272,7 +1274,7 @@
     if( crt->version == 3 )
 #endif
     {
-        ret = x509_get_crt_ext( &p, end, crt, cb );
+        ret = x509_get_crt_ext( &p, end, crt, cb, p_ctx );
         if( ret != 0 )
         {
             mbedtls_x509_crt_free( crt );
@@ -1336,7 +1338,8 @@
                                                 const unsigned char *buf,
                                                 size_t buflen,
                                                 int make_copy,
-                                                mbedtls_x509_crt_ext_cb_t cb )
+                                                mbedtls_x509_crt_ext_cb_t cb,
+                                                void *p_ctx )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_x509_crt *crt = chain, *prev = NULL;
@@ -1368,7 +1371,7 @@
         crt = crt->next;
     }
 
-    ret = x509_crt_parse_der_core( crt, buf, buflen, make_copy, cb );
+    ret = x509_crt_parse_der_core( crt, buf, buflen, make_copy, cb, p_ctx );
     if( ret != 0 )
     {
         if( prev )
@@ -1387,23 +1390,24 @@
                                        const unsigned char *buf,
                                        size_t buflen )
 {
-    return( mbedtls_x509_crt_parse_der_internal( chain, buf, buflen, 0, NULL ) );
+    return( mbedtls_x509_crt_parse_der_internal( chain, buf, buflen, 0, NULL, NULL ) );
 }
 
 int mbedtls_x509_crt_parse_der_with_ext_cb( mbedtls_x509_crt *chain,
                                             const unsigned char *buf,
                                             size_t buflen,
                                             int make_copy,
-                                            mbedtls_x509_crt_ext_cb_t cb )
+                                            mbedtls_x509_crt_ext_cb_t cb,
+                                            void *p_ctx )
 {
-    return( mbedtls_x509_crt_parse_der_internal( chain, buf, buflen, make_copy, cb ) );
+    return( mbedtls_x509_crt_parse_der_internal( chain, buf, buflen, make_copy, cb, p_ctx ) );
 }
 
 int mbedtls_x509_crt_parse_der( mbedtls_x509_crt *chain,
                                 const unsigned char *buf,
                                 size_t buflen )
 {
-    return( mbedtls_x509_crt_parse_der_internal( chain, buf, buflen, 1, NULL ) );
+    return( mbedtls_x509_crt_parse_der_internal( chain, buf, buflen, 1, NULL, NULL ) );
 }
 
 /*