diff --git a/userspace/ksud/src/mount.rs b/userspace/ksud/src/mount.rs
index 424f02e8..37b49723 100644
--- a/userspace/ksud/src/mount.rs
+++ b/userspace/ksud/src/mount.rs
@@ -149,6 +149,7 @@ fn mount_overlayfs(
     Mount::builder()
         .fstype(FilesystemType::from("overlay"))
         .data(&options)
+        .flags(MountFlags::RDONLY)
         .mount(KSU_OVERLAY_SOURCE, dest.as_ref())
         .with_context(|| {
             format!(