diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 9ee68198f60..f5f736160f5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -90,6 +90,12 @@ jobs:
         run: cargo build --locked
         working-directory: rustls
 
+        # this target does _not_ include the libstd crate in its sysroot
+        # it will catch unwanted usage of libstd in _dependencies_
+      - name: cargo build (debug; default features; no-std)
+        run: cargo build --locked --no-default-features --target x86_64-unknown-none
+        working-directory: rustls
+
       - name: cargo test (debug; default features)
         run: cargo test --locked
         working-directory: rustls