diff --git a/src/openvpn/ssl_mbedtls.c b/src/openvpn/ssl_mbedtls.c
index 8aaca96..9561abb 100644
--- a/src/openvpn/ssl_mbedtls.c
+++ b/src/openvpn/ssl_mbedtls.c
@@ -481,6 +481,7 @@
             status = mbedtls_pk_parse_key(
                 ctx->priv_key, (const unsigned char *)priv_key_file, strlen(priv_key_file) + 1,
                 (unsigned char *)passbuf, strlen(passbuf));
+            secure_memzero(passbuf, sizeof(passbuf));
         }
     }
     else
@@ -491,6 +492,7 @@
             char passbuf[512] = { 0 };
             pem_password_callback(passbuf, 512, 0, NULL);
             status = mbedtls_pk_parse_keyfile(ctx->priv_key, priv_key_file, passbuf);
+            secure_memzero(passbuf, sizeof(passbuf));
         }
     }
     if (!mbed_ok(status))