diff --git a/externals/zexy/src/strcmp.c b/externals/zexy/src/strcmp.c
index 69fe95357598adc14308a948335b2e99f8695935..2d9f8ce937ee74db82fa7cf74412f60ff5476299 100644
--- a/externals/zexy/src/strcmp.c
+++ b/externals/zexy/src/strcmp.c
@@ -79,7 +79,7 @@ static void list2binbuf(t_binbuf**bbuf, int *n, char**str, int argc,
   i=*n;
   s=*str;
 
-  if(' '==s[i]) {
+  if(s && ' '==s[i]) {
     s[i]=0;
   }
 }