diff --git a/ChangeLog b/ChangeLog
index afbe2f689..0bc75bac0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,13 @@ mbed TLS ChangeLog (Sorted per branch, date)
 
 = mbed TLS 2.x.x branch released xxxx-xx-xx
 
+Security
+   * The deterministic ECDSA calculation reused the scheme's HMAC-DRBG to
+     implement blinding. Because of this for the same key and message the same
+     blinding value was generated. This reduced the effectiveness of the
+     countermeasure and leaked information about the private key through side
+     channels. Reported by Jack Lloyd.
+
 Features
    * Add MBEDTLS_REMOVE_3DES_CIPHERSUITES to allow removing 3DES ciphersuites
      from the default list (enabled by default). See