Microsoft Warns of Two Actively Exploited Defender Vulnerabilities
Summary: Microsoft disclosed that CVE-2026-41091, a link-following privilege escalation flaw in Defender rated 7.8 on CVSS, and CVE-2026-45498, a denial-of-service bug rated 4.0, have both come under active exploitation in the wild. The flaws were fixed in Microsoft Defender Antimalware Platform versions 1.1.26040.8 and 4.18.26040.7, and CISA added both to its KEV catalog with a June 3, 2026 remediation deadline for FCEB agencies.
What you should know: The exploited escalation bug lets an authorized attacker reach SYSTEM privileges locally, and Huntress has already observed exploitation of both flaws alongside BlueHammer (CVE-2026-33825) - a third Microsoft vulnerability flagged as exploited within a single week.