Microsoft Ships KB5087420 May 2026 Patch Tuesday Update for Windows 11 23H2
The May 2026 Patch Tuesday cumulative update for Windows 11 23H2 patches kernel and security vulnerabilities. Companion to KB5089549 (24H2/25H2). Build 22631.7100.
On this page
Key takeaways
- May 2026 Patch Tuesday cumulative update for Windows 11 23H2.
- Build 22631.7100. Companion to KB5089549 (24H2/25H2).
- Supersedes KB5082052 (April). Mandatory security update.
What to do now
High urgency- Install KB5087420 as part of May Patch Tuesday.
Microsoft released KB5087420 on May 12, 2026, the May Patch Tuesday cumulative security update for Windows 11 23H2, raising the build to 22631.7100 with kernel security patches and April preview fixes.
KB5087420 is the May 2026 Patch Tuesday update for Windows 11 23H2 with kernel security fixes.
May Patch Tuesday for Win 11 23H2. Build 22631.7100. Kernel patches. Supersedes KB5082052.
Affected & context
May 2026 Patch Tuesday for Windows 11 23H2.
Monthly security patches for a widely deployed Windows 11 branch.
Windows 11 23H2, all editions.
- Vendors
- Microsoft
- Products
- Windows 11 23H2
KB5087420 Delivers May 2026 Security Fixes for Windows 11 23H2
Microsoft released KB5087420 on May 12, 2026, the May Patch Tuesday cumulative security update for Windows 11 Version 23H2. The update raises the OS build to 22631.7100 and includes security patches plus non-security improvements from the April optional preview. It is the 23H2-specific companion to KB5089549 (24H2/25H2).
The update addresses kernel-level security vulnerabilities, system stability improvements, and rolls in fixes from the April preview cycle. As a mandatory Patch Tuesday update, it is delivered automatically through Windows Update.
23H2 Remains a Supported Branch
Windows 11 23H2 continues to receive monthly security updates as a supported branch. Organizations that have not yet migrated to 24H2 or 25H2 should install this update as part of standard Patch Tuesday maintenance.
Windows 11 23H2 All Editions
Windows 11 23H2, all editions (Home, Pro, Enterprise, Education), x64 and ARM64. Build 22631.7100. Mandatory security update. Supersedes KB5082052 (April).
Timeline
KB5087420 released
Microsoft releases KB5087420 as May Patch Tuesday for Windows 11 23H2.
Source: Microsoft
Confidence: High
Impact
May Patch Tuesday security update for Windows 11 23H2.
Business impact
Kernel security patches protect against privilege escalation.
Affected audience: Windows 11 23H2 users and IT admins
Action required.
Response
Response status: Patched
Patch available: Yes
Workaround available: No
FAQ
What does KB5087420 fix?
Kernel-level security vulnerabilities plus non-security improvements from the April preview. Build 22631.7100.
Which systems need this?
Windows 11 23H2, all editions, x64 and ARM64.
Is this mandatory?
Yes. It is a mandatory Patch Tuesday security update.
The bottom line
KB5087420 is the May 2026 Patch Tuesday cumulative update for Windows 11 23H2. Patches kernel vulnerabilities, includes April preview fixes. Build 22631.7100.
Standard monthly Patch Tuesday update for 23H2. Install alongside the .NET Framework update KB5087058.
What happens next
The June 2026 update KB5093998 will supersede KB5087420.
What to do
Install KB5087420 and verify Build 22631.7100.