diff --git a/sys/riscv/riscv/exception.S b/sys/riscv/riscv/exception.S
--- a/sys/riscv/riscv/exception.S
+++ b/sys/riscv/riscv/exception.S
@@ -104,6 +104,11 @@
 	sd	t0, (TF_SEPC)(sp)
 	csrr	t0, sstatus
 	sd	t0, (TF_SSTATUS)(sp)
+.if \mode == 1
+	/* Disable user address access for supervisor mode exceptions. */
+	li	t0, SSTATUS_SUM
+	csrc	sstatus, t0
+.endif
 	csrr	t0, stval
 	sd	t0, (TF_STVAL)(sp)
 	csrr	t0, scause