diff --git a/mongoose.c b/mongoose.c
index 4c72be82..f860ab3b 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -14581,6 +14581,7 @@ static STACK_OF(X509_INFO) * load_ca_certs(struct mg_str ca) {
 static bool add_ca_certs(SSL_CTX *ctx, STACK_OF(X509_INFO) * certs) {
   int i;
   X509_STORE *cert_store = SSL_CTX_get_cert_store(ctx);
+  if (cert_store == NULL) return false;
   for (i = 0; i < sk_X509_INFO_num(certs); i++) {
     X509_INFO *cert_info = sk_X509_INFO_value(certs, i);
     if (cert_info->x509 && !X509_STORE_add_cert(cert_store, cert_info->x509))
diff --git a/src/tls_openssl.c b/src/tls_openssl.c
index 37838d95..f51d6dd8 100644
--- a/src/tls_openssl.c
+++ b/src/tls_openssl.c
@@ -39,6 +39,7 @@ static STACK_OF(X509_INFO) * load_ca_certs(struct mg_str ca) {
 static bool add_ca_certs(SSL_CTX *ctx, STACK_OF(X509_INFO) * certs) {
   int i;
   X509_STORE *cert_store = SSL_CTX_get_cert_store(ctx);
+  if (cert_store == NULL) return false;
   for (i = 0; i < sk_X509_INFO_num(certs); i++) {
     X509_INFO *cert_info = sk_X509_INFO_value(certs, i);
     if (cert_info->x509 && !X509_STORE_add_cert(cert_store, cert_info->x509))