Microsoft released update KB5122878 on September 8, 2026, for Windows 10 version 22H2 and Enterprise LTSC 2021, marking one of the most significant security releases in the operating system’s history. This update arrives as part of a record-breaking September 2026 Patch Tuesday that addresses 974 unique vulnerabilities across the Microsoft ecosystem.
The unprecedented volume of security flaws—nearly triple the monthly average seen in 2024—is largely attributed to Microsoft’s internal deployment of AI-powered vulnerability discovery systems. These automated tools have accelerated the identification of “long-tail” security bugs, resulting in what industry analysts are calling a “patch apocalypse” for IT departments managing legacy infrastructure.
Critical Zero-Day Exploits Fixed
While the sheer number of patches is high, the immediate priority for administrators involves two vulnerabilities that were actively exploited in the wild prior to the release of KB5122878.
The first, identified as CVE-2026-85880, is an elevation of privilege vulnerability within the Windows Advanced Local Procedure Call (ALPC). The second, CVE-2026-81963, targets the Windows Update Stack to achieve similar privilege elevation. Both flaws allow attackers to gain system-level permissions on a compromised machine, making them high-priority targets for remediation.
Securing Windows 10 for Free
As Windows 10 enters its extended support phase, the KB5122878 update is delivered through the Extended Security Update (ESU) program. While the standard consumer enrollment fee is set at $30, Microsoft has introduced non-traditional methods for users to secure their devices without direct payment.
According to official support documentation, Windows 10 users can obtain a free ESU license by redeeming 1,000 Microsoft Rewards points. Additionally, some users may qualify for free enrollment by syncing specific PC settings across their Microsoft accounts. These options are intended to maintain a security baseline for the millions of devices that remain ineligible for Windows 11 due to hardware requirements.
For commercial environments, the pricing structure remains more rigid. Business licenses for Year 1 of the ESU program start at $61 per device. This cost is scheduled to double annually over a three-year period, a pricing model designed to encourage corporate migration to more modern hardware and operating systems.
Impact of AI on Security Maintenance
The transition to AI-assisted bug hunting marks a shift in how Microsoft maintains its software. While the high CVE count in KB5122878 indicates a more secure codebase by clearing out dormant flaws, it also increases the testing burden on organizations. Security researchers note that while the volume of identified flaws has spiked, many of the AI-discovered vulnerabilities require specific, complex conditions to exploit, which may differ from the high-risk profile of the active zero-days also included in this month’s release.
