Add ChangeLog entry
diff --git a/ChangeLog b/ChangeLog
index 348864c..19bdb79 100644
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+++ b/ChangeLog
@@ -2,6 +2,21 @@
= mbed TLS x.x.x branch released xxxx-xx-xx
+Security
+ * Fix a vulnerability in TLS ciphersuites based on CBC and using SHA-384,
+ in (D)TLS 1.0 to 1.2, that allowed an active network attacker to
+ partially recover the plaintext of messages under some conditions by
+ exploiting timing measurements. With DTLS, the attacker could perform
+ this recovery by sending many messages in the same connection. With TLS
+ or if mbedtls_ssl_conf_dtls_badmac_limit() was used, the attack only
+ worked if the same secret (for example a HTTP Cookie) has been repeatedly
+ sent over connections manipulated by the attacker. Connections using GCM
+ or CCM instead of CBC, using hash sizes other than SHA-384, or using
+ Encrypt-then-Mac (RFC 7366) were not affected. The vulnerability was
+ caused by a miscalculation (for SHA-384) in a countermeasure to the
+ original Lucky 13 attack. Found by Kenny Paterson, Eyal Ronen and Adi
+ Shamir.
+
API Changes
* Extend the platform module with a util component that contains
functionality shared by multiple Mbed TLS modules. At this stage