diff --git a/test/shell.d/windows-vm-compose-test.sh b/test/shell.d/windows-vm-compose-test.sh
index 77c298a8..0495e1e0 100644
--- a/test/shell.d/windows-vm-compose-test.sh
+++ b/test/shell.d/windows-vm-compose-test.sh
@@ -183,6 +183,29 @@ resolve_caller
 [[ $(stat -Lc '%d:%i' "$EXPECTED_STORAGE") == $(stat -Lc '%d:%i' "$external_storage") ]] || fail "symlink target not pinned"
 pass "legitimate caller-owned symlinks remain in place"
 
+# Reproduce the original post-validation race at the last possible moment:
+# replace the familiar shared path with / only after the final guard returns,
+# inside the mocked Docker Compose invocation. Compose must still consume the
+# protected anchor bound to the inode that was validated earlier.
+raced_shared="$HOME/Windows.before-race"
+shared_id_before_race=$(stat -Lc '%d:%i' "$external_shared2")
+race_ran=0
+dc() {
+  [[ $1 == up && ${2:-} == -d ]] || return 1
+  mv -T -- "$HOME/Windows" "$raced_shared"
+  ln -s / "$HOME/Windows"
+  race_ran=1
+  [[ $(get_mount_source /shared) == "$EXPECTED_SHARED" ]] || return 1
+  [[ $(stat -Lc '%d:%i' "$EXPECTED_SHARED") == "$shared_id_before_race" ]] || return 1
+}
+__priv_up || fail "post-validation home-path swap changed the Docker mount source"
+(( race_ran == 1 )) || fail "post-validation race hook did not run"
+[[ -L $HOME/Windows && $(readlink "$HOME/Windows") == / ]] || fail "race did not replace the familiar shared path"
+rm "$HOME/Windows"
+mv -T -- "$raced_shared" "$HOME/Windows"
+unset -f dc
+pass "a post-validation path swap cannot redirect Docker away from the pinned shared inode"
+
 # Same-inode sources fail before mounting and close both descriptors.
 reset_case
 same="$TMPDIR/same-source"
diff --git a/test/shell.d/windows-vm-mount-boundary-test.sh b/test/shell.d/windows-vm-mount-boundary-test.sh
index 509143b2..a49e5652 100644
--- a/test/shell.d/windows-vm-mount-boundary-test.sh
+++ b/test/shell.d/windows-vm-mount-boundary-test.sh
@@ -119,6 +119,26 @@ if setpriv --reuid=1001 --regid=1001 --clear-groups cat "$EXPECTED_SHARED/shared
 fi
 pass "cross-filesystem symlink sources bind by identity and migrated 0700 leaves deny another account"
 
+# Existing production boundary components are never repaired in place when
+# their ownership or write permissions are unsafe. Both the preparation path
+# and the final pre-Docker guard must fail closed without disturbing the binds.
+chmod 0731 "$MOUNT_ROOT"
+with_vm_lock prepare_caller_mounts 2>/dev/null && fail "root repaired a group-writable mount boundary instead of rejecting it"
+mounts_ready 2>/dev/null && fail "final guard accepted a group-writable mount boundary"
+[[ $(command stat -Lc '%a' "$MOUNT_ROOT") == 731 ]] || fail "rejection unexpectedly changed the writable boundary"
+chmod 0711 "$MOUNT_ROOT"
+
+chown 1000:1000 "$USERS_DIR"
+with_vm_lock prepare_caller_mounts 2>/dev/null && fail "root repaired a caller-owned mount boundary instead of rejecting it"
+mounts_ready 2>/dev/null && fail "final guard accepted a caller-owned mount boundary"
+[[ $(command stat -Lc '%u' "$USERS_DIR") == 1000 ]] || fail "rejection unexpectedly changed the boundary owner"
+chown root:root "$USERS_DIR"
+
+[[ $(mount_layer_count "$EXPECTED_STORAGE") == 1 &&
+  $(mount_layer_count "$EXPECTED_SHARED") == 1 ]] || fail "boundary rejection changed the verified mount pair"
+mounts_ready || fail "restored production boundaries were rejected"
+pass "root rejects wrong-owned and group-writable production mount boundaries without mutation"
+
 expected_space=$(command df -P -- /home/storage-target | awk 'NR==2 {print int($4/1024/1024)}')
 actual_space=$(available_storage_gb)
 [[ $actual_space == "$expected_space" ]] || fail "disk-space helper did not measure the storage target filesystem"