AMD's patch for its Zen 1 'Division by zero' bug was not fully effective, leading to a second patch being issued. The original bug could have allowed attackers to retrieve sensitive information from the CPU's registers. The initial patch was intended to wipe any old data, but it was found that by the time the security provision was activated, a speculative execution attack could have already progressed too far. AMD and Intel have both been hit with vulnerability disclosures this month, but AMD's new solution does not come with additional overhead.