diff --git a/src/bn/relic_bn_smb.c b/src/bn/relic_bn_smb.c
index d1446ae0e..3c84d5237 100644
--- a/src/bn/relic_bn_smb.c
+++ b/src/bn/relic_bn_smb.c
@@ -112,6 +112,8 @@ int bn_smb_jac(const bn_t a, const bn_t b) {
 			bi = ci = 0;
 
 			i = RLC_MAX(t0->used, t1->used);
+			bn_grow(t0, i);
+			bn_grow(t1, i);
 			dv_zero(t0->dp + t0->used, i - t0->used);
 			dv_zero(t1->dp + t1->used, i - t1->used);
 			if (i == 1) {