diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
index a36f5eb310..bb874f7f50 100644
--- a/src/interfaces/libpq/fe-exec.c
+++ b/src/interfaces/libpq/fe-exec.c
@@ -3917,6 +3917,8 @@ PQsetnonblocking(PGconn *conn, int arg)
 int
 PQisnonblocking(const PGconn *conn)
 {
+	if (!conn || conn->status == CONNECTION_BAD)
+		return false;
 	return pqIsnonblocking(conn);
 }
 
@@ -3936,6 +3938,8 @@ PQisthreadsafe(void)
 int
 PQflush(PGconn *conn)
 {
+	if (!conn || conn->status == CONNECTION_BAD)
+		return -1;
 	return pqFlush(conn);
 }
 
diff --git a/src/interfaces/libpq/fe-secure-openssl.c b/src/interfaces/libpq/fe-secure-openssl.c
index 8117cbd40f..3cc75380e0 100644
--- a/src/interfaces/libpq/fe-secure-openssl.c
+++ b/src/interfaces/libpq/fe-secure-openssl.c
@@ -1938,7 +1938,7 @@ err:
 int
 PQdefaultSSLKeyPassHook_OpenSSL(char *buf, int size, PGconn *conn)
 {
-	if (conn->sslpassword)
+	if (conn && conn->sslpassword)
 	{
 		if (strlen(conn->sslpassword) + 1 > size)
 			fprintf(stderr, libpq_gettext("WARNING: sslpassword truncated\n"));