diff --git a/externals/iemlib/iemlib1/src/vcf_filter~.c b/externals/iemlib/iemlib1/src/vcf_filter~.c
index 0990b0ae8751b7cbffddcfbc1b497528146657a3..f4a78f5da25b52ff79e3295cf4a29c15f5bdd03a 100644
--- a/externals/iemlib/iemlib1/src/vcf_filter~.c
+++ b/externals/iemlib/iemlib1/src/vcf_filter~.c
@@ -321,7 +321,8 @@ static void *vcf_filter_tilde_new(t_symbol *filt_typ)
   x->x_wn1 = 0.0;
   x->x_wn2 = 0.0;
   c = (char *)filt_typ->s_name;
-  c[5] = 0;
+  if (strlen(c) > 5)
+    c[5] = 0;
   strcpy(x->x_filtname, c);
   return(x);
 }