diff --git a/ChangeLog b/ChangeLog
index 1e2f9b871..46d60e17f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,6 +9,8 @@ Bugfix
      Philippe Antoine.
    * Clarify documentation for mbedtls_ssl_write() to include 0 as a valid
      return value. Found by @davidwu2000. #839
+   * Fix the key_app_writer example which was writing a leading zero byte which
+     was creating an invalid ASN.1 tag. Found by Aryeh R. Fixes #1257.
 
 = mbed TLS 2.7.4 branch released 2018-06-18