KB5087420

Microsoft security update released 2026-05-12. Fixes 56 CVEs.

Critical

Download KB5087420

Get the official update for KB5087420. The download and file size for each supported product are on the Microsoft Update Catalog page.

Microsoft Update Catalog: download KB5087420 Microsoft support article

Update summary

Released

2026-05-12

CVEs fixed

Max CVSS

9.8

Severity

Critical

Exploitation and severity

Fixes 56 CVEs. Most severe CVSS 9.8 (Critical). EPSS exploit probability up to 2.4%.

Among the lower half of tracked Microsoft updates by EPSS exploit probability.

What to do

Elevated priority: high severity or a meaningful exploitation probability, sooner if an affected product is internet-facing. Senserva flags whether KB5087420 is missing on your devices.

Affected products

Windows 10 Version 1809 for 32-bit Systems
Windows 10 Version 1809 for x64-based Systems
Windows Server 2019

References

Microsoft support article Microsoft Security Update Guide

See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.