'As Facebook and Apple have said, Microsoft confirmed we had a security problem,' Microsoft said in a statement. 'Some computers, including some Macs, are infected with malicious code like some other companies. There is no evidence of customer data being affected and we are still investigating. '
Microsoft is not the only company leaking information about vulnerabilities and reporting errors. Mozilla also fell into a similar situation in 2015 but they decided to say the whole thing.
Kaspersky also acknowledged being attacked by Duqu 2.0 APT. Bitdefender also suffered data leaks in 2015.