diff --git a/sys/arm64/arm64/freebsd32_machdep.c b/sys/arm64/arm64/freebsd32_machdep.c
index a6719b6e436e..aeac4605f2f5 100644
--- a/sys/arm64/arm64/freebsd32_machdep.c
+++ b/sys/arm64/arm64/freebsd32_machdep.c
@@ -284,6 +284,7 @@ freebsd32_swapcontext(struct thread *td, struct freebsd32_swapcontext_args *uap)
 	if (uap->oucp == NULL || uap->ucp == NULL)
 		ret = EINVAL;
 	else {
+		bzero(&uc, sizeof(uc));
 		get_mcontext32(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
 		PROC_LOCK(td->td_proc);
 		uc.uc_sigmask = td->td_sigmask;