diff --git a/arch/arm/src/arm/Toolchain.defs b/arch/arm/src/arm/Toolchain.defs
index a9299a0b3a3..2505e484620 100644
--- a/arch/arm/src/arm/Toolchain.defs
+++ b/arch/arm/src/arm/Toolchain.defs
@@ -80,7 +80,7 @@ ifeq ($(CONFIG_ARCH_COVERAGE),y)
 endif
 
 ifeq ($(CONFIG_MM_KASAN),y)
-  ARCHCPUFLAGS += -fsanitize=kernel-address
+  ARCHOPTIMIZATION += -fsanitize=kernel-address
 endif
 
 # NuttX buildroot under Linux or Cygwin
diff --git a/arch/arm/src/armv6-m/Toolchain.defs b/arch/arm/src/armv6-m/Toolchain.defs
index 6fe3f986f77..781ed9dcfb6 100644
--- a/arch/arm/src/armv6-m/Toolchain.defs
+++ b/arch/arm/src/armv6-m/Toolchain.defs
@@ -154,7 +154,7 @@ endif
 # Architecture flags
 
 ifeq ($(CONFIG_MM_KASAN),y)
-  ARCHCPUFLAGS += -fsanitize=kernel-address
+  ARCHOPTIMIZATION += -fsanitize=kernel-address
 endif
 
 ARCHCFLAGS += -fno-common
diff --git a/arch/arm/src/armv7-a/Toolchain.defs b/arch/arm/src/armv7-a/Toolchain.defs
index 3c8580b3442..f1672fe0c5b 100644
--- a/arch/arm/src/armv7-a/Toolchain.defs
+++ b/arch/arm/src/armv7-a/Toolchain.defs
@@ -97,7 +97,7 @@ else
 endif
 
 ifeq ($(CONFIG_MM_KASAN),y)
-  ARCHCPUFLAGS += -fsanitize=kernel-address
+  ARCHOPTIMIZATION += -fsanitize=kernel-address
 endif
 
 ifeq ($(CONFIG_DEBUG_CUSTOMOPT),y)
diff --git a/arch/arm/src/armv7-m/Toolchain.defs b/arch/arm/src/armv7-m/Toolchain.defs
index 98fc328bfce..f35c285a96e 100644
--- a/arch/arm/src/armv7-m/Toolchain.defs
+++ b/arch/arm/src/armv7-m/Toolchain.defs
@@ -172,7 +172,7 @@ endif
 endif
 
 ifeq ($(CONFIG_MM_KASAN),y)
-  ARCHCPUFLAGS += -fsanitize=kernel-address
+  ARCHOPTIMIZATION += -fsanitize=kernel-address
 endif
 
 # Generic GNU EABI toolchain
diff --git a/arch/arm/src/armv7-r/Toolchain.defs b/arch/arm/src/armv7-r/Toolchain.defs
index 6e59529dde2..73fe52a469a 100644
--- a/arch/arm/src/armv7-r/Toolchain.defs
+++ b/arch/arm/src/armv7-r/Toolchain.defs
@@ -97,7 +97,7 @@ ifeq ($(CONFIG_ENDIAN_BIG),y)
 endif
 
 ifeq ($(CONFIG_MM_KASAN),y)
-  ARCHCPUFLAGS += -fsanitize=kernel-address
+  ARCHOPTIMIZATION += -fsanitize=kernel-address
 endif
 
 ifeq ($(CONFIG_ENDIAN_BIG),y)
diff --git a/arch/arm/src/armv8-m/Toolchain.defs b/arch/arm/src/armv8-m/Toolchain.defs
index 08056ef0f20..f7c59fa2695 100644
--- a/arch/arm/src/armv8-m/Toolchain.defs
+++ b/arch/arm/src/armv8-m/Toolchain.defs
@@ -181,7 +181,7 @@ endif
 endif
 
 ifeq ($(CONFIG_MM_KASAN),y)
-  ARCHCPUFLAGS += -fsanitize=kernel-address
+  ARCHOPTIMIZATION += -fsanitize=kernel-address
 endif
 
 # Generic GNU EABI toolchain
diff --git a/arch/arm/src/tlsr82/Toolchain.defs b/arch/arm/src/tlsr82/Toolchain.defs
index 113637c3d32..f689caafe84 100644
--- a/arch/arm/src/tlsr82/Toolchain.defs
+++ b/arch/arm/src/tlsr82/Toolchain.defs
@@ -141,7 +141,7 @@ endif
 # Architecture flags
 
 ifeq ($(CONFIG_MM_KASAN),y)
-  ARCHCPUFLAGS += -fsanitize=kernel-address
+  ARCHOPTIMIZATION += -fsanitize=kernel-address
 endif
 
 ARCHCFLAGS += -fno-common
diff --git a/arch/risc-v/src/common/Toolchain.defs b/arch/risc-v/src/common/Toolchain.defs
index 21554495a0e..269db180fa2 100644
--- a/arch/risc-v/src/common/Toolchain.defs
+++ b/arch/risc-v/src/common/Toolchain.defs
@@ -153,7 +153,7 @@ ifeq ($(CONFIG_RISCV_TOOLCHAIN),GNU_RVG)
 endif
 
 ifeq ($(CONFIG_MM_KASAN),y)
-  ARCHCPUFLAGS += -fsanitize=kernel-address
+  ARCHOPTIMIZATION += -fsanitize=kernel-address
 endif
 
 # Default toolchain
diff --git a/arch/xtensa/src/lx6/Toolchain.defs b/arch/xtensa/src/lx6/Toolchain.defs
index 5a0f32e7a47..09df1986a0e 100644
--- a/arch/xtensa/src/lx6/Toolchain.defs
+++ b/arch/xtensa/src/lx6/Toolchain.defs
@@ -44,7 +44,7 @@ endif
 ARCHCPUFLAGS = -mlongcalls
 
 ifeq ($(CONFIG_MM_KASAN),y)
-  ARCHCPUFLAGS += -fsanitize=kernel-address
+  ARCHOPTIMIZATION += -fsanitize=kernel-address
 endif
 
 ifeq ($(CONFIG_DEBUG_CUSTOMOPT),y)
diff --git a/arch/xtensa/src/lx7/Toolchain.defs b/arch/xtensa/src/lx7/Toolchain.defs
index 496bbcbf5d0..2d05a6be4c4 100644
--- a/arch/xtensa/src/lx7/Toolchain.defs
+++ b/arch/xtensa/src/lx7/Toolchain.defs
@@ -44,7 +44,7 @@ endif
 ARCHCPUFLAGS = -mlongcalls
 
 ifeq ($(CONFIG_MM_KASAN),y)
-  ARCHCPUFLAGS += -fsanitize=kernel-address
+  ARCHOPTIMIZATION += -fsanitize=kernel-address
 endif
 
 ifeq ($(CONFIG_DEBUG_CUSTOMOPT),y)
diff --git a/boards/sim/sim/sim/scripts/Make.defs b/boards/sim/sim/sim/scripts/Make.defs
index a2fde55e7e4..f5666425e86 100644
--- a/boards/sim/sim/sim/scripts/Make.defs
+++ b/boards/sim/sim/sim/scripts/Make.defs
@@ -71,6 +71,16 @@ ifeq ($(CONFIG_ARCH_COVERAGE),y)
   ARCHOPTIMIZATION += -fprofile-generate -ftest-coverage
 endif
 
+ifeq ($(CONFIG_SIM_ASAN),y)
+  ARCHOPTIMIZATION += -fsanitize=address
+else ifeq ($(CONFIG_MM_KASAN),y)
+  ARCHOPTIMIZATION += -fsanitize=kernel-address
+endif
+
+ifeq ($(CONFIG_SIM_UBSAN),y)
+  ARCHOPTIMIZATION += -fsanitize=undefined
+endif
+
 # Add -fno-common because macOS "ld -r" doesn't seem to pick objects
 # for common symbols.
 ARCHCFLAGS = -fno-common -ffunction-sections -fdata-sections
@@ -141,19 +151,6 @@ ifeq ($(CONFIG_LIBCXX),y)
   CXXFLAGS += -D_LIBCPP_DISABLE_AVAILABILITY
 endif
 
-ifeq ($(CONFIG_SIM_ASAN),y)
-  CFLAGS += -fsanitize=address
-  CXXFLAGS += -fsanitize=address
-else ifeq ($(CONFIG_MM_KASAN),y)
-  CFLAGS += -fsanitize=kernel-address
-  CXXFLAGS += -fsanitize=kernel-address
-endif
-
-ifeq ($(CONFIG_SIM_UBSAN),y)
-  CFLAGS += -fsanitize=undefined
-  CXXFLAGS += -fsanitize=undefined
-endif
-
 # Loadable module definitions
 
 CMODULEFLAGS = $(CFLAGS)