diff --git a/ChangeLog b/ChangeLog
index c92e42953..c2dac3e73 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,12 @@ mbed TLS ChangeLog (Sorted per branch, date)
 
 = mbed TLS 2.16.x branch released xxxx-xx-xx
 
+Security
+   * Fix side channel vulnerability in ECDSA key generation. Obtaining precise
+     timings on the comparison in the key generation enabled the attacker to
+     learn leading bits of the ephemeral key used during ECDSA signatures and to
+     recover the private key. Reported by Jeremy Dubeuf.
+
 Bugfix
    * Remove redundant line for getting the bitlen of a bignum, since the variable
      holding the returned value is overwritten a line after.