diff --git a/ChangeLog.d/fix_kdf_correct_initial_capacity.txt b/ChangeLog.d/fix_kdf_correct_initial_capacity.txt
new file mode 100644
index 0000000000..6eeffd7777
--- /dev/null
+++ b/ChangeLog.d/fix_kdf_correct_initial_capacity.txt
@@ -0,0 +1,3 @@
+Bugfix
+   * Correct initial capacities for key derivation algorithms:TLS12_PRF, 
+     TLS12_PSK_TO_MS, PBKDF2-HMAC, PBKDF2-CMAC