diff --git a/ChangeLog b/ChangeLog
index 9d591bb1e..641ce1635 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -31,6 +31,8 @@ Bugfix
      a contribution from Tobias Tangemann. #541
    * Fixed cert_app sample program for debug output and for use when no root
      certificates are provided.
+   * Fixed pthread implementation to avoid unintended double initialisations
+     and double frees. (found by Niklas Amnebratt)
    * Fixed the sample applications gen_key.c, cert_req.c and cert_write.c for
      builds where the configuration MBEDTLS_PEM_WRITE_C is not defined. Found
      by inestlerode. #559.