diff --git a/tools/cmake/common.cmake b/tools/cmake/common.cmake
index 429587eb..12730b9b 100644
--- a/tools/cmake/common.cmake
+++ b/tools/cmake/common.cmake
@@ -7,6 +7,10 @@
 
 set(PROJECT_VER "0.2.1")
 
+# esp-idf sets the C++ standard weird. Set cmake vars to match.
+set(CMAKE_CXX_STANDARD 23)
+set(CMAKE_CXX_EXTENSIONS ON)
+
 # Build only the subset of components that we actually depend on.
 set(COMPONENTS "")