Google experts discovered a new variant of Rowhammer attack against RAM memory cards that bypasses all current defenses. Google said that it is currently working with several semiconductor industry players to search possible solutions for the Rowhammer phenomenon Google encouraged fellow experts to join their efforts as the challenge is substantial and the ramifications are industry-wide The new Half-Double attack triggers bit flips at a distance of two rows from the hammered row instead of the canonical one used in previous variants of the attack.”]
Source: https://securityaffairs.co/wordpress/118284/hacking/rowhammer-variant-dubbed-half-double.html