Microsoft's June 2026 Patch Tuesday is the largest on record, fixing more than 200 vulnerabilities (independent counts put the total above 206), including three publicly disclosed zero-days that are not yet being exploited. The standout is CVE-2026-45586, a Windows CTFMON elevation-of-privilege flaw that grants SYSTEM access, which matches the GreenPlasma bug a researcher dropped in protest of Microsoft's bug-bounty handling; a BitLocker bypass called YellowKey was also fixed. The update includes 33 critical flaws, most of them remote code execution, hitting Remote Desktop, Hyper-V, Office, and cryptographic services. Microsoft flagged 15 issues as more likely to be exploited soon.
Microsoft fixed 120 vulnerabilities on Tuesday - 17 Critical, no zero-days for the first time since June 2024. Two Word RCEs (CVE-2026-40361 and CVE-2026-40364) trigger just by viewing a malicious document in Outlook's Preview Pane and are rated 'Exploitation More Likely.' Windows DNS Client (CVE-2026-41096) lets an attacker-controlled DNS server execute code on any Windows machine resolving a hostile name - echoing SigRed. Other priorities: Netlogon RCE (CVE-2026-41089) and Microsoft SSO Plugin for Jira and Confluence (CVE-2026-41103, CVSS 9.1).
Microsoft confirmed yesterday that a Windows Shell spoofing flaw, CVE-2026-32202, is being exploited in the wild. The bug lets an attacker craft files that appear in File Explorer with fake names, icons, and paths - so a malicious .exe can show up looking like a benign PDF, leading users to double-click and run it. Microsoft patched the bug in the April 14 Patch Tuesday but only confirmed in-the-wild exploitation on April 28, raising urgency for any environment that hasn't deployed April patches. The flaw is particularly dangerous on shared file servers, USB drops, and email attachments - any path where users trust File Explorer to tell them what's what.
Microsoft has released out-of-band emergency updates to fix two Windows Server issues introduced by the April 2026 Patch Tuesday updates. First issue: some admins experienced failures installing the KB5082063 security update on Windows Server 2025. Second issue: Patch Tuesday cumulative updates caused Windows servers running domain controller roles to enter restart loops due to crashes of the Local Security Authority Subsystem Service (LSASS). The restart loop can also hit newly-set-up domain controllers or existing ones if the server processes authentication requests very early during startup. The Windows Server 2025 OOB update (KB5091157) addresses both issues. OOB updates for other supported Windows Server versions address only the domain controller restart issue. This is the third consecutive year where April Windows Server patches have caused authentication-related breakage, following similar incidents in 2024 and 2025.