From cde7d82391fd9c08493448ac0945c4be13245773 Mon Sep 17 00:00:00 2001
From: Marcus Bointon <marcus@synchromedia.co.uk>
Date: Thu, 22 Oct 2020 08:26:02 +0200
Subject: [PATCH] Wrap calls to openssl_pkey_free in version checks, fixes
 #2178

---
 src/PHPMailer.php | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/PHPMailer.php b/src/PHPMailer.php
index 0b4c407d..95f00327 100644
--- a/src/PHPMailer.php
+++ b/src/PHPMailer.php
@@ -4526,11 +4526,15 @@ class PHPMailer
             $privKey = openssl_pkey_get_private($privKeyStr);
         }
         if (openssl_sign($signHeader, $signature, $privKey, 'sha256WithRSAEncryption')) {
-            openssl_pkey_free($privKey);
+            if (PHP_MAJOR_VERSION < 8) {
+                openssl_pkey_free($privKey);
+            }
 
             return base64_encode($signature);
         }
-        openssl_pkey_free($privKey);
+        if (PHP_MAJOR_VERSION < 8) {
+            openssl_pkey_free($privKey);
+        }
 
         return '';
     }