diff --git a/ChangeLog.d/pkwrite-pem-use-heap.txt b/ChangeLog.d/pkwrite-pem-use-heap.txt
new file mode 100644
index 000000000..d2e7129ec
--- /dev/null
+++ b/ChangeLog.d/pkwrite-pem-use-heap.txt
@@ -0,0 +1,4 @@
+Changes
+   * Use heap memory to allocate DER encoded RSA public/private key.
+     This reduces stack usage significantly for writing a public/private
+     key to a PEM string.