TL;DR: Microsoft’s June 2026 Patch Tuesday is the largest in history: 206 CVEs + 3 actively exploited zero-days. Sysadmin priorities: (1) CVE-2026-49160 “HTTP/2 Bomb” (HTTP.sys DoS, crashes IIS web servers), (2) BitLocker encryption bypass (YellowKey variant), (3) CTF EoP (GreenPlasma). Patch immediately; for IIS servers, registry-based mitigation (MaxHeadersCount) provides temporary protection.

3 active zero-days — summary

CVE	Component	Type	CVSS	Impact
CVE-2026-49160	HTTP.sys (under IIS)	DoS	7.5	Web server crash, service outage
CVE-2026-50507 (CTF EoP, “GreenPlasma”)	Windows Collaborative Translation Framework	EoP	7.8	Privilege escalation (user → SYSTEM)
BitLocker bypass (“YellowKey”)	BitLocker disk encryption	Auth Bypass	6.8	Attacker with physical access can bypass disk encryption

Method 1 — IIS servers: HTTP/2 Bomb mitigation

If you can’t patch immediately, reduce DoS risk by limiting HTTP.sys header counts. Microsoft introduced a new registry key (MaxHeadersCount):

; Registry path:
HKLMSystemCurrentControlSetServicesHTTPParameters

; New DWORD:
MaxHeadersCount = 100   ; Default: unlimited. Recommended: 100-500

; Via command line:
reg add "HKLMSystemCurrentControlSetServicesHTTPParameters" /v MaxHeadersCount /t REG_DWORD /d 100 /f
net stop http /y
net start w3svc

Warning: This is temporary mitigation only. Apply the actual patch (KB varies by OS) as soon as possible.

Method 2 — Domain Controller patch sequence

1. Patch a test DC first and monitor for 24 hours (especially watch for the KB5082063 DC restart loop not recurring)
2. Start with one DC per site; leave others as backup
3. Patch FSMO role holders last (rollback risk minimized)
4. Run health checks on each DC: dcdiag /v and repadmin /replsummary
5. Test authentication: user login, GPO push, DNS lookup

Method 3 — BitLocker bypass exposure

The “YellowKey” variant lets an attacker with physical access bypass BitLocker. Attack vector typically exploits recovery key manipulation or a flaw in PCR validation.

• Push the BitLocker patch to all endpoints on the same day (via Intune or WSUS) on laptops and tablets
• Verify recovery keys are correctly backed up to Active Directory or Entra ID (manage-bde -protectors -get C:)
• After patching, PCR values are recalculated on all devices — verify TPM binding
• Review lost/stolen device policy: remote wipe any pre-patch missing devices (Intune wipe)

Method 4 — VS Code GitHub token protection

A VS Code extension vulnerability can leak stored GitHub personal access tokens externally.

1. Update VS Code to the latest version (Help → Check for Updates)
2. Rotate all PATs on GitHub (Settings → Developer Settings → Tokens)
3. Where possible, use gh auth login with device flow; avoid long-lived PATs
4. Minimize repository access scope (use fine-grained PATs instead of classic)

General patch procedure and verification

# List installed hotfixes (PowerShell)
Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 10

# Check whether a specific KB is installed
Get-HotFix -Id KB5094139   # Example: Exchange June 2026 SU

# Post-WSUS/Intune compliance report
Get-WindowsUpdateLog

Common issues

• “Too many patches — what do I install first?” AI-accelerated vulnerability discovery may make this volume “the new normal.” Follow vendor priority analysis from Tenable, CrowdStrike, etc.
• “HTTPS cert error after IIS patch.” HTTP/2 changes may affect TLS certificate binding. Check with netsh http show sslcert and rebind with netsh http add sslcert if needed.
• “PCR 0 changed after BitLocker patch.” Expected — similar to BIOS/firmware change. Sign in once with recovery key; BitLocker auto-rebinds.
• “VS Code extensions broken after update.” Reinstall affected extensions from the marketplace; long-unmaintained extensions may be incompatible.

Sources: Krebs on Security, BleepingComputer, Tenable, CrowdStrike Patch Tuesday analyses. Tested environments: Windows Server 2019 / 2022 / 2025, IIS 10.0, Exchange SE / 2019 CU15. Last updated: 2026-06-15.