diff --git a/modules/libcom/RTEMS/posix/rtems_config.c b/modules/libcom/RTEMS/posix/rtems_config.c
index d0a123b6d..c9fa8a8d7 100644
--- a/modules/libcom/RTEMS/posix/rtems_config.c
+++ b/modules/libcom/RTEMS/posix/rtems_config.c
@@ -60,7 +60,8 @@ extern void *POSIX_Init(void *argument);
 #define CONFIGURE_APPLICATION_NEEDS_STUB_DRIVER
 #define CONFIGURE_APPLICATION_NEEDS_ZERO_DRIVER
 
-#define CONFIGURE_MAXIMUM_FILE_DESCRIPTORS 150
+/* Max FDs cannot exceed FD_SETSIZE from newlib (64) */
+#define CONFIGURE_MAXIMUM_FILE_DESCRIPTORS 64
 #define CONFIGURE_IMFS_ENABLE_MKFIFO    2
 
 #define CONFIGURE_MAXIMUM_NFS_MOUNTS 		3