A hacker gained access to nearly 50 million Facebook user accounts by exploiting a weakness in the social network’s systems, Facebook said on Friday.

Microsoft has patched a vulnerability in the Cortana smart assistant that could have allowed an attacker with access to a locked computer to use the smart assistant and access data on the device, execute malicious code, or even change the PC’s password to access the device in its entirety.

Destructive malware intent on sabotaging PCs is to blame for the IT problems reported during the PyeongChang 2018 Winter Olympics opening ceremony. The issues, first reported on Friday by UK paper The Guardian, consisted of failing Internet and television systems for on-site journalists attending and reporting the opening ceremony.

Lenovo has fixed a high-severity vulnerability in a wide range of laptop models that allowed hackers with physical access to log in and then obtain users’ Windows login credentials and other sensitive data.

Over the course of the current week, WordPress sites around the globe have been the targets of a massive brute-force campaign during which hackers attempted to guess admin account logins in order to install a Monero miner on compromised sites.