diff --git a/extern/backward/CMakeLists.txt b/extern/backward/CMakeLists.txt
index 97327ccd1..73169ed42 100644
--- a/extern/backward/CMakeLists.txt
+++ b/extern/backward/CMakeLists.txt
@@ -20,7 +20,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION 3.0...3.20)
 project(backward CXX)
 
 # Introduce variables:
diff --git a/extern/emu2413/CMakeLists.txt b/extern/emu2413/CMakeLists.txt
index 83e154ac1..381986b68 100644
--- a/extern/emu2413/CMakeLists.txt
+++ b/extern/emu2413/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION 3.0...3.20)
 project(emu2413)
 
 if(MSVC)
diff --git a/extern/fftw/CMakeLists.txt b/extern/fftw/CMakeLists.txt
index 6b807c486..b08dd7d03 100644
--- a/extern/fftw/CMakeLists.txt
+++ b/extern/fftw/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required (VERSION 3.0)
+cmake_minimum_required (VERSION 3.0...3.20)
 
 if (NOT DEFINED CMAKE_BUILD_TYPE)
   set (CMAKE_BUILD_TYPE Release CACHE STRING "Build type")
diff --git a/extern/freetype/CMakeLists.txt b/extern/freetype/CMakeLists.txt
index 8dbca01e6..a8c4d5d5b 100644
--- a/extern/freetype/CMakeLists.txt
+++ b/extern/freetype/CMakeLists.txt
@@ -110,7 +110,7 @@
 
 # To minimize the number of cmake_policy() workarounds,
 # CMake >= 3 is requested.
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION 3.0...3.20)
 
 if (NOT CMAKE_VERSION VERSION_LESS 3.3)
   # Allow symbol visibility settings also on static libraries. CMake < 3.3
diff --git a/extern/pfd-fixed/CMakeLists.txt b/extern/pfd-fixed/CMakeLists.txt
index 3be61ae5a..2a20dbbfa 100644
--- a/extern/pfd-fixed/CMakeLists.txt
+++ b/extern/pfd-fixed/CMakeLists.txt
@@ -1,6 +1,6 @@
-cmake_minimum_required(VERSION 3.1.0)
+cmake_minimum_required(VERSION 3.1...3.20)
 
 project(portable_file_dialogs VERSION 1.00 LANGUAGES CXX)
 
 add_library(${PROJECT_NAME} INTERFACE)
-target_include_directories(${PROJECT_NAME} INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})
\ No newline at end of file
+target_include_directories(${PROJECT_NAME} INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})
diff --git a/extern/rtmidi/CMakeLists.txt b/extern/rtmidi/CMakeLists.txt
index e0ef4ca09..d48e56d28 100644
--- a/extern/rtmidi/CMakeLists.txt
+++ b/extern/rtmidi/CMakeLists.txt
@@ -3,7 +3,7 @@
 # additional modifications for Furnace by tildearrow.
 
 # Set minimum CMake required version for this project.
-cmake_minimum_required(VERSION 3.5)
+cmake_minimum_required(VERSION 3.5...3.20)
 
 # Define a C++ project.
 project(RtMidi LANGUAGES CXX C)
diff --git a/extern/vgsound_emu-modified/CMakeLists.txt b/extern/vgsound_emu-modified/CMakeLists.txt
index 0aea2e92a..b70b4b28e 100644
--- a/extern/vgsound_emu-modified/CMakeLists.txt
+++ b/extern/vgsound_emu-modified/CMakeLists.txt
@@ -6,7 +6,7 @@
 # CMake for vgsound_emu
 #
 
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION 3.0...3.20)
 project(vgsound_emu
 	VERSION 2.1.1
 	LANGUAGES CXX)
@@ -233,4 +233,4 @@ endif()
 target_include_directories(${PROJECT_NAME} INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})
 
 # for Test purpose (GCC)
-# target_compile_options(vgsound_emu PRIVATE -Wall -Wextra -Werror)
\ No newline at end of file
+# target_compile_options(vgsound_emu PRIVATE -Wall -Wextra -Werror)
diff --git a/extern/zlib/CMakeLists.txt b/extern/zlib/CMakeLists.txt
index 380ca472d..a49f4bb24 100644
--- a/extern/zlib/CMakeLists.txt
+++ b/extern/zlib/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 2.4.4)
+cmake_minimum_required(VERSION 3.0...3.20)
 set(CMAKE_ALLOW_LOOSE_LOOP_CONSTRUCTS ON)
 
 project(zlib C)