Microsoft released KB5087420 on May 12, 2026, the May Patch Tuesday update for Windows 11 23H2 (Build 22631.7079). Per the official KB, it fixes the Remote Desktop Connection security warning dialog rendering issue from April's KB5082052 on multi-monitor setups and continues Secure Boot certificate rollout.
A standard Patch Tuesday update that fixes the April RDP regression and continues the Secure Boot certificate transition ahead of the June 2026 expiration deadline.
Key takeaways
- Build 22631.7079. May Patch Tuesday security update.
- Fixes RDP multi-monitor warning rendering issue from KB5082052 (April).
- Secure Boot certificate targeting improvements continue.
- 120 security flaws addressed, zero exploited zero-days (May PT total).
Affected
KB5087420 Delivers May Patch Tuesday for Windows 11 23H2
Microsoft released KB5087420 on May 12, 2026, the May Patch Tuesday cumulative update for Windows 11 23H2. Per Microsoft's official KB article, the update raises the OS build to 22631.7079 and includes security fixes plus quality improvements from the April update KB5082052.
Per the official changelog, the update fixes the Remote Desktop Connection security warning dialog rendering issue that appeared on multi-monitor setups with different scaling after installing KB5082052 (April). It also continues Secure Boot certificate rollout with additional high-confidence device targeting data, and addresses the BitLocker recovery behavior from April's Secure Boot updates.
120 Flaws Patched, Zero Zero-Days in May Patch Tuesday
Per HTMD Blog, the May 2026 Patch Tuesday addresses 120 security flaws across Windows products with zero exploited zero-days. The RDP warning fix is important for enterprises using multi-monitor setups with Remote Desktop. Per Windows Forum, this update is part of a broader platform transition involving Secure Boot cert rollover, SmartScreen improvements, and AI component servicing.
Windows 11 23H2, All Editions
Windows 11 23H2, all editions, x64 and ARM64. Build 22631.7079. Mandatory security update. Superseded by KB5093998 (June) and KB5099414 (July). No new known issues reported.
Timeline
Impact & actions
May Patch Tuesday with 120 security fixes, RDP warning fix, and Secure Boot cert targeting for Windows 11 23H2.
Recommended actions · Medium urgency
- 1Install KB5099414 (latest for 23H2).
- 2Verify RDP warnings render correctly on multi-monitor setups.
Response
FAQ
What does KB5087420 fix?
Security fixes from May Patch Tuesday (120 flaws, 0 zero-days), RDP multi-monitor warning fix from April, Secure Boot certificate targeting improvements, BitLocker recovery fix.
Is KB5087420 the latest update for 23H2?
No. KB5099414 (July 2026, Build 22631.7376) is the latest for Windows 11 23H2.
Which systems need this update?
Windows 11 23H2, all editions, x64 and ARM64. Build 22631.7079.
The bottom line
KB5087420 delivers May 2026 Patch Tuesday for Windows 11 23H2 with 120 security fixes, RDP multi-monitor warning fix, and Secure Boot cert targeting.
What happens next
What to do
