Microsoft Warns of Two Actively Exploited Zero-Day Vulnerabilities in Active Directory Federation Services and SharePoint Server

Microsoft has issued a warning regarding two zero-day vulnerabilities, CVE-2026-56155 and CVE-2026-56164, which are actively being exploited in the wild. CVE-2026-56155 is an elevation of privilege vulnerability in Active Directory Federation Services, while CVE-2026-56164 affects Microsoft SharePoint Server, also allowing for privilege escalation. Users are urged to prioritize applying the latest security updates to mitigate the risk of account takeover and broader system compromise.