--- socat-orig/socat-1.7.4.1/xio-openssl.c	2021-01-10 04:57:35.000000000 -0800
+++ socat-1.7.4.1/xio-openssl.c	2021-07-12 03:17:23.772269622 -0700
@@ -1777,15 +1777,17 @@
 #if WITH_IP6
 			case 16: /* IPv6 */
 			   inet_ntop(AF_INET6, data, aBuffer, sizeof(aBuffer));
-			   xioip6_pton(peername, &ip6bin);
-			   if (memcmp(data, &ip6bin, sizeof(ip6bin)) == 0) {
-			      Debug2("subjectAltName \"%s\" matches peername \"%s\"",
-				    aBuffer, peername);
-			      ok = 1;
-			   } else {
-			      Info2("subjectAltName \"%s\" does not match peername \"%s\"",
-				    aBuffer, peername);
-			   }			      
+               if (peername != NULL) {
+			      xioip6_pton(peername, &ip6bin);
+			      if (memcmp(data, &ip6bin, sizeof(ip6bin)) == 0) {
+			         Debug2("subjectAltName \"%s\" matches peername \"%s\"",
+				       aBuffer, peername);
+			         ok = 1;
+			      } else {
+			         Info2("subjectAltName \"%s\" does not match peername \"%s\"",
+				      aBuffer, peername);
+                  }
+               }
 			   break;
 #endif
 			}