diff --git a/ext/openssl/openssl.c b/ext/openssl/openssl.c
index c6ee21dd6be..41294f979a7 100644
--- a/ext/openssl/openssl.c
+++ b/ext/openssl/openssl.c
@@ -2256,6 +2256,7 @@ static EVP_PKEY * php_openssl_evp_from_zval(zval ** val, int public_key, char *
 		} else {
 			tmp = **zphrase;
 			zval_copy_ctor(&tmp);
+			convert_to_string(&tmp);
 			passphrase = Z_STRVAL(tmp);
 		}