Russian hacking group RomCom exploited zero-day vulnerabilities in Mozilla Firefox and Microsoft Windows to launch widespread cyberattacks targeting users in Europe and North America, with both vulnerabilities now patched.

ESET Research details the analysis of a previously unknown vulnerability in Mozilla products exploited in the wild and another previously unknown Microsoft Windows vulnerability, combined in a zero-click exploit.

The Russian hacking group also chained the attack with a previously unknown vulnerability in Windows 10 and 11 to install a backdoor on the victim computers.