Microsoft released mandatory Windows 11 security updates that fix vulnerabilities affecting supported systems. The cumulative updates KB5124008 for Windows 11 25H2 and 24H2, and KB5122880 for 23H2, include the September 2026 Patch Tuesday security fixes; this article does not identify specific CVEs, but says the release includes broad security patching alongside non-security feature and reliability changes.
Why it matters: Windows 11 users and organizations should install these updates promptly because they are mandatory security releases that address a large set of vulnerabilities. For defenders, this is a routine but important patching event: verify deployment across 23H2, 24H2, and 25H2 systems.
Lawrence Abrams
2026.09.08
88% relevant
This source adds the parallel Windows 10 ESU rollout for September 2026, specifically KB5122878 for Windows 10 and LTSC systems, and notes it includes that month’s Patch Tuesday fixes plus a BitLocker Group Policy known-issue fix and Secure Boot certificate-targeting changes.
Mayank Parmar
2026.09.08
100% relevant
This article establishes a distinct September 2026 Windows 11 Patch Tuesday rollout, identified by the specific KB updates and affected Windows 11 versions.
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