Microsoft is investigating whether a leak from its early alert system for cybersecurity companies allowed Chinese hackers to exploit flaws in its SharePoint service before they were patched, Bloomberg News reported on Friday.

Microsoft is investigating a potential leak within its MAPP program, suspecting that Chinese state-backed hackers exploited SharePoint vulnerabilities before patches were widely available. The security flaw,

Threat actors exploit SharePoint flaws to access internal systems, steal sensitive data, and carry out surveillance, impersonation, and extortion.