diff --git a/ChangeLog b/ChangeLog
index f03d507..9d591bb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -34,6 +34,8 @@
    * 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.
+   * Fixed pthread implementation to avoid unintended double initialisations
+     and double frees. (found by Niklas Amnebratt)
    * Fixed default threading implementation to avoid accidental double
      initialisations and double frees.
    * Fix mbedtls_x509_get_sig() to update the ASN1 type in the mbedtls_x509_buf