Google, Microsoft say Chinese hackers are exploiting SharePoint zero-day

Security researchers report active exploitation of a Microsoft SharePoint zero-day (CVE-2025-53770) that allows attackers to steal private keys, plant malware, and access internal data; Microsoft attributes campaigns to multiple China‑backed groups (Linen Typhoon, Violet Typhoon, Storm-2603) and says patches have been released but self-hosted SharePoint instances should assume compromise.