Limit size of the rndBuf
diff --git a/mangle.c b/mangle.c
index 2a1364e..02e2e0e 100644
--- a/mangle.c
+++ b/mangle.c
@@ -178,6 +178,9 @@
 static void mangle_Random(uint8_t * buf, size_t bufSz, size_t off)
 {
     uint64_t sz = util_rndGet(1, bufSz - off);
+    if (sz > 4096ULL) {
+        sz = 4096ULL;
+    }
     util_rndBuf(&buf[off], sz);
 }