diff -up openssl-3.0.0-alpha16/crypto/bio/bio_addr.c.use-explicit openssl-3.0.0-alpha16/crypto/bio/bio_addr.c
--- openssl-3.0.0-alpha16/crypto/bio/bio_addr.c.use-explicit	2021-07-06 14:06:05.706578389 +0200
+++ openssl-3.0.0-alpha16/crypto/bio/bio_addr.c	2021-07-06 14:07:24.482329505 +0200
@@ -696,7 +696,7 @@ int BIO_lookup_ex(const char *host, cons
         hints.ai_protocol = protocol;
 # ifdef AI_ADDRCONFIG
 #  ifdef AF_UNSPEC
-        if (family == AF_UNSPEC)
+        if (host != NULL && family == AF_UNSPEC)
 #  endif
             hints.ai_flags |= AI_ADDRCONFIG;
 # endif