diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3962c760..240c105c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## 0.5.1 - TBD
+
+- Prevent potential memory corruption when working with large vectors that cannot be allocated on the stack.
+
 ## 0.5 - April 14, 2017
 
 Features
diff --git a/runtime.c b/runtime.c
index b998c144..95ff779a 100644
--- a/runtime.c
+++ b/runtime.c
@@ -2236,6 +2236,7 @@ object Cyc_make_vector(void *data, object cont, int argc, object len, ...)
   int i, ulen;
   size_t element_vec_size;
   va_list ap;
+  make_pair(tmp_pair, NULL, NULL);
   va_start(ap, len);
   if (argc > 1) {
     fill = va_arg(ap, object);
@@ -2261,6 +2262,10 @@ object Cyc_make_vector(void *data, object cont, int argc, object len, ...)
     ((vector) v)->tag = vector_tag;
     ((vector) v)->num_elements = ulen;
     ((vector) v)->elements = (object *)(((char *)v) + sizeof(vector_type));
+    // Use write barrier to ensure fill is moved to heap if it is on the stack
+    // Otherwise if next minor GC misses fill it could be catastrophic
+    car(&tmp_pair) = fill;
+    add_mutation(data, &tmp_pair, -1, fill);
   } else {
     v = alloca(sizeof(vector_type));
     ((vector) v)->hdr.mark = gc_color_red;