diff --git a/tools/m4/Makefile b/tools/m4/Makefile
index eaa46ec4f8..84898904fe 100644
--- a/tools/m4/Makefile
+++ b/tools/m4/Makefile
@@ -8,11 +8,11 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=m4
 PKG_CPE_ID:=cpe:/a:gnu:m4
-PKG_VERSION:=1.4.20
+PKG_VERSION:=1.4.21
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=@GNU/$(PKG_NAME)
-PKG_HASH:=6ac4fc31ce440debe63987c2ebbf9d7b6634e67a7c3279257dc7361de8bdb3ef
+PKG_HASH:=38ae59f7a30bf9c108193cc5c25fbb06014f21e230c7ede2eff614f7b7c37ed8
 
 HOST_BUILD_PARALLEL:=1