diff --git a/crates/home/src/windows.rs b/crates/home/src/windows.rs
index bd21ad085..e03cb315a 100644
--- a/crates/home/src/windows.rs
+++ b/crates/home/src/windows.rs
@@ -46,7 +46,7 @@ fn home_dir_crt() -> Option<PathBuf> {
     None
 }
 
-extern "C" {
+unsafe extern "C" {
     fn wcslen(buf: *const u16) -> usize;
 }
 
diff --git a/src/cargo/util/cpu.rs b/src/cargo/util/cpu.rs
index 6ebb01b8e..df63648c9 100644
--- a/src/cargo/util/cpu.rs
+++ b/src/cargo/util/cpu.rs
@@ -108,7 +108,7 @@ mod imp {
     const CPU_STATE_NICE: usize = 3;
     const CPU_STATE_MAX: usize = 4;
 
-    extern "C" {
+    unsafe extern "C" {
         static mut mach_task_self_: mach_port_t;
 
         fn mach_host_self() -> mach_port_t;