diff --git a/libs/CLI11/include/CLI/Validators.hpp b/libs/CLI11/include/CLI/Validators.hpp
index 536f8a6..3371905 100644
--- a/libs/CLI11/include/CLI/Validators.hpp
+++ b/libs/CLI11/include/CLI/Validators.hpp
@@ -18,6 +18,7 @@
 // Could be swapped for filesystem in C++17
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <cstdint>
 
 namespace CLI {