diff --git a/StringUtils.c b/StringUtils.c
index 0578cdea..84b69b64 100644
--- a/StringUtils.c
+++ b/StringUtils.c
@@ -30,8 +30,9 @@ char* String_cat(const char* s1, const char* s2) {
    int l1 = strlen(s1);
    int l2 = strlen(s2);
    char* out = xMalloc(l1 + l2 + 1);
-   strncpy(out, s1, l1);
-   strncpy(out+l1, s2, l2+1);
+   memcpy(out, s1, l1);
+   memcpy(out+l1, s2, l2+1);
+   out[l1 + l2] = '\0';
    return out;
 }