diff --git a/library/x509.c b/library/x509.c
index 380fec2..1826f1d 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -361,6 +361,8 @@
             MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
         return( MBEDTLS_ERR_X509_INVALID_NAME + ret );
 
+    end = *p + len;
+
     if( ( end - *p ) < 1 )
         return( MBEDTLS_ERR_X509_INVALID_NAME +
                 MBEDTLS_ERR_ASN1_OUT_OF_DATA );
@@ -394,6 +396,12 @@
     val->p = *p;
     *p += val->len;
 
+    if( *p != end )
+    {
+        return( MBEDTLS_ERR_X509_INVALID_NAME +
+                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
+    }
+
     cur->next = NULL;
 
     return( 0 );