Developers from the Bitcoin Core project teem discovered a denial-of-service vulnerability in Bitcoin Core exploitable by miners. The entire Bitcoin blockchain was at risk of being pulled down by one single DDos attack.
Bitcoin Core developers have made the following statement:
A denial-of-service vulnerability (CVE-2018-17144) exploitable by miners has been discovered in Bitcoin Core versions 0.14.0 up to 0.16.2. It is recommended to upgrade any of the vulnerable versions to 0.16.3 as soon as possible.