Updated change log

Author: Mika Leppänen

CHANGELOG.md

@@ -12,7 +12,8 @@
 * Prevent sending broadcast frames on unicast channel
 * Delay sending of the first DIO message until parent selection is made and DAO target is published. Fix is made to avoid sending of DIO messages to the unstable network.
 * Accept only next possible BSI for detect BR reboot. This fix a bug when PAN timeout happen and node join correctly to new but hear old BSI after that.
-*Adaptation layer push buffer back to queue when confirmation status is MLME_TRANSACTION_OVERFLOW  and block new MAC data request until it got proper confirmation status.
+* Adaptation layer push buffer back to queue when confirmation status is MLME_TRANSACTION_OVERFLOW  and block new MAC data request until it got proper confirmation status.
+* Corrected radius message memory allocation by adding NULL check to recover from memory exhaustion.
 
 
 ## Release v12.6.2 (09-11-2020)