diff --git a/package/ndisc6/Config.in b/package/ndisc6/Config.in
index 6abe4ce2ea..095b2e8174 100644
--- a/package/ndisc6/Config.in
+++ b/package/ndisc6/Config.in
@@ -4,6 +4,7 @@ comment "ndisc6 requires a toolchain with IPv6 support"
 config BR2_PACKAGE_NDISC6
 	bool "ndisc6 tools"
 	depends on BR2_INET_IPV6
+	depends on BR2_USE_MMU # fork()
 	select BR2_PACKAGE_GETTEXT if BR2_NEEDS_GETTEXT_IF_LOCALE
 	help
 	  NDisc6 is a small collection of useful tools for IPv6 networking