diff --git a/library/x509_ocsp.c b/library/x509_ocsp.c
index af50530ab6..a555f0a0bb 100644
--- a/library/x509_ocsp.c
+++ b/library/x509_ocsp.c
@@ -52,6 +52,7 @@ static void mbedtls_zeroize( void *v, size_t n ) {
 
 void mbedtls_x509_ocsp_response_init( mbedtls_x509_ocsp_response *resp )
 {
+    memset( resp, 0, sizeof( mbedtls_x509_ocsp_response ) );
 }
 
 void mbedtls_x509_ocsp_response_free( mbedtls_x509_ocsp_response *resp )