diff --git a/CMakeLists.txt b/CMakeLists.txt
index 77dde15..6eda5c5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -403,7 +403,7 @@ else()
   else()
     set(ARCH_FLAG "-march=${ARCH}")
   endif()
-  set(WARNINGS "-Wall -Wextra -Wpointer-arith -Wundef -Wvla -Wwrite-strings -Wno-error=extra -Wno-error=deprecated-declarations -Wno-unused-parameter -Wno-unused-variable -Wno-error=unused-variable -Wno-error=undef -Wno-error=uninitialized")
+  set(WARNINGS "-Wall -Wextra -Wpointer-arith -Wvla -Wwrite-strings -Wno-error=extra -Wno-error=deprecated-declarations -Wno-unused-parameter -Wno-unused-variable -Wno-error=unused-variable -Wno-error=uninitialized")
   if(NOT MINGW)
     set(WARNINGS_AS_ERRORS_FLAG "-Werror")
   endif()
diff --git a/external/CMakeLists.txt b/external/CMakeLists.txt
index 93366a4..d384aa8 100644
--- a/external/CMakeLists.txt
+++ b/external/CMakeLists.txt
@@ -63,8 +63,6 @@ else()
   set_property(TARGET libminiupnpc-static PROPERTY FOLDER "external")
   if(MSVC)
     set_property(TARGET libminiupnpc-static APPEND_STRING PROPERTY COMPILE_FLAGS " -wd4244 -wd4267")
-  elseif(NOT MSVC)
-    set_property(TARGET libminiupnpc-static APPEND_STRING PROPERTY COMPILE_FLAGS " -Wno-undef -Wno-unused-result -Wno-unused-value")
   endif()
 
   set(UPNP_STATIC true PARENT_SCOPE)
diff --git a/tests/libwallet_api_tests/CMakeLists.txt b/tests/libwallet_api_tests/CMakeLists.txt
index 4c5542d..9505ab7 100644
--- a/tests/libwallet_api_tests/CMakeLists.txt
+++ b/tests/libwallet_api_tests/CMakeLists.txt
@@ -59,7 +59,7 @@ if (NOT MSVC)
   set_property(TARGET libwallet_api_tests
     APPEND_STRING
     PROPERTY
-      COMPILE_FLAGS " -Wno-undef -Wno-sign-compare")
+      COMPILE_FLAGS " -Wno-sign-compare")
 endif ()
 
 add_test(
diff --git a/tests/net_load_tests/CMakeLists.txt b/tests/net_load_tests/CMakeLists.txt
index 78d670c..be60671 100644
--- a/tests/net_load_tests/CMakeLists.txt
+++ b/tests/net_load_tests/CMakeLists.txt
@@ -75,5 +75,5 @@ set_property(TARGET net_load_tests_clt net_load_tests_srv
 if(NOT MSVC)
   set_property(TARGET net_load_tests_clt net_load_tests_srv APPEND_STRING
     PROPERTY
-      COMPILE_FLAGS " -Wno-undef -Wno-sign-compare")
+      COMPILE_FLAGS " -Wno-sign-compare")
 endif()
diff --git a/tests/unit_tests/CMakeLists.txt b/tests/unit_tests/CMakeLists.txt
index 1dac92b..5fe7c2e 100644
--- a/tests/unit_tests/CMakeLists.txt
+++ b/tests/unit_tests/CMakeLists.txt
@@ -95,7 +95,7 @@ if (NOT MSVC)
   set_property(TARGET unit_tests
     APPEND_STRING
     PROPERTY
-      COMPILE_FLAGS " -Wno-undef -Wno-sign-compare")
+      COMPILE_FLAGS " -Wno-sign-compare")
 endif ()
 
 add_test(