Recently, a vulnerability was discovered that allows third parties to inject malicious code into replay files. This code is executed automatically when opening the compromised replays via the game client. Your system may be at risk if you download potentially modified replays from the internet.
This vulnerability is set to be fixed in the very near future, in World of Tanks Update 9.5 and World of Warplanes Update 1.7. Keep an eye on these games' portals and social media outlets to see when these updates are available.
We would also like to point out that even replays provided by players on our official forums may also be dangerous.
Thank you for your understanding.