diff --git a/sys/compat/linux/linux_fork.c b/sys/compat/linux/linux_fork.c
--- a/sys/compat/linux/linux_fork.c
+++ b/sys/compat/linux/linux_fork.c
@@ -64,6 +64,7 @@
 #include <compat/linux/linux_emul.h>
 #include <compat/linux/linux_fork.h>
 #include <compat/linux/linux_futex.h>
+#include <compat/linux/linux_mib.h>
 #include <compat/linux/linux_misc.h>
 #include <compat/linux/linux_util.h>
 
@@ -411,6 +412,20 @@
 	if (uca->stack != 0 && uca->stack_size == 0)
 		return (EINVAL);
 
+	/* Verify that no unsupported flags are passed along. */
+	if ((uca->flags & LINUX_CLONE_NEWTIME) != 0) {
+		LINUX_RATELIMIT_MSG("unsupported clone3 option CLONE_NEWTIME");
+		return (ENOSYS);
+	}
+	if ((uca->flags & LINUX_CLONE_INTO_CGROUP) != 0) {
+		LINUX_RATELIMIT_MSG("unsupported clone3 option CLONE_INTO_CGROUP");
+		return (ENOSYS);
+	}
+	if (uca->set_tid != 0 || uca->set_tid_size != 0) {
+		LINUX_RATELIMIT_MSG("unsupported clone3 set_tid");
+		return (ENOSYS);
+	}
+
 	return (0);
 }