diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index 4cb106c..e6cce93 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -1063,7 +1063,7 @@ pg_GSS_recvauth(Port *port)
 	 */
 	if (pg_krb_server_keyfile != NULL && pg_krb_server_keyfile[0] != '\0')
 	{
-		if (setenv("KRB5_KTNAME", pg_krb_server_keyfile, 1) != 0)
+		if (_putenv_s("KRB5_KTNAME", pg_krb_server_keyfile) != 0)
 		{
 			/* The only likely failure cause is OOM, so use that errcode */
 			ereport(FATAL,
diff --git a/src/backend/libpq/be-secure-gssapi.c b/src/backend/libpq/be-secure-gssapi.c
index 211634f..a45437f 100644
--- a/src/backend/libpq/be-secure-gssapi.c
+++ b/src/backend/libpq/be-secure-gssapi.c
@@ -527,7 +527,7 @@ secure_open_gssapi(Port *port)
 	 */
 	if (pg_krb_server_keyfile != NULL && pg_krb_server_keyfile[0] != '\0')
 	{
-		if (setenv("KRB5_KTNAME", pg_krb_server_keyfile, 1) != 0)
+		if (_putenv_s("KRB5_KTNAME", pg_krb_server_keyfile) != 0)
 		{
 			/* The only likely failure cause is OOM, so use that errcode */
 			ereport(FATAL,