Microsoft stock up 0.62% in pre-market amid Office zero-day patch and data center approval

Microsoft released emergency security updates to address an actively exploited zero-day vulnerability in Office (CVE-2026-21509) and simultaneously secured approval for 15 additional data centers in Mount Pleasant, Wisconsin, supporting its AI and cloud expansion efforts.

• The security flaw, which requires user interaction via malicious files, was detected in wild attacks, prompting CISA to add it to its Known Exploited Vulnerabilities catalog.
• MSFT is trading higher in pre-market at $473.19, representing a gain of 0.62%.