diff --git a/3rdparty/civetweb/civetweb.cmake b/3rdparty/civetweb/civetweb.cmake
index 5f5f68520e9..4a4c0de61c8 100644
--- a/3rdparty/civetweb/civetweb.cmake
+++ b/3rdparty/civetweb/civetweb.cmake
@@ -18,6 +18,7 @@ ExternalProject_Add(
         -DCIVETWEB_ENABLE_DEBUG_TOOLS=OFF
         -DCIVETWEB_DISABLE_CGI=ON
         -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
+        -DCMAKE_POLICY_VERSION_MINIMUM=3.5
         -DCMAKE_CXX_FLAGS="-D_GLIBCXX_USE_CXX11_ABI=$<BOOL:${GLIBCXX_USE_CXX11_ABI}> $<$<PLATFORM_ID:Windows>:/EHsc>"
         ${ExternalProject_CMAKE_ARGS_hidden}
     BUILD_BYPRODUCTS
diff --git a/3rdparty/librealsense/librealsense.cmake b/3rdparty/librealsense/librealsense.cmake
index d57ba037acc..a6e1002d8bb 100644
--- a/3rdparty/librealsense/librealsense.cmake
+++ b/3rdparty/librealsense/librealsense.cmake
@@ -31,6 +31,7 @@ ExternalProject_Add(
         -DBUILD_PYTHON_BINDINGS=OFF
         -DBUILD_WITH_CUDA=${BUILD_CUDA_MODULE}
         -DUSE_EXTERNAL_USB=ON
+        -DCMAKE_POLICY_VERSION_MINIMUM=3.5
         # Syncing GLIBCXX_USE_CXX11_ABI for MSVC causes problems, but directly
         # checking CXX_COMPILER_ID is not supported.
         $<IF:$<PLATFORM_ID:Windows>,"",-DCMAKE_CXX_FLAGS=-D_GLIBCXX_USE_CXX11_ABI=$<BOOL:${GLIBCXX_USE_CXX11_ABI}>>