Key Takeaways
- ESU-Exclusive Update: KB5073724 is only available to Windows 10 Extended Security Updates subscribers. It upgrades systems to Build 19045.6809 (22H2) and Build 19044.6809 (LTSC) with security patches until October 2026.
- Critical Security Patches: This update fixes 114 security vulnerabilities, including 3 actively exploited zero-day threats, 57 Elevation of Privilege flaws, and a critical Desktop Window Manager exploit that allowed unauthorized memory access.
- Legacy Hardware Changes: Microsoft has removed outdated modem drivers (Agere/LSI and Motorola SM56-era chipsets), affecting fewer than 0.01% of users, and is deploying new Secure Boot certificates to replace expired ones for enhanced system protection.
- No Feature Updates: As Windows 10 is in maintenance mode, KB5073724 focuses exclusively on security improvements and bug fixes—no new features or UI changes are included, with all development efforts now directed toward Windows 11.
Quick Links
What is Windows 10 KB5073724?
This update is exclusively available to users who have enrolled in the ESU program ESU, as Windows 10’s mainstream support officially ended in October 2025. Installing KB5073724 upgrades your system to Windows 10 Build 19045.6809, while LTSC (Long-Term Servicing Channel) users receive Build 19044.6809.
Removal of Legacy Modem Drivers
The most significant change in this update is the removal of outdated modem drivers. Microsoft has discontinued support for:
- agrsm.sys / agrsm64.sys – Used by Agere (formerly Lucent) and LSI modem chipsets
- smserial.sys / smserl64.sys – Developed by Motorola for SM56-era modems
These drivers were primarily found in older laptops and desktops from the early 2000s. Microsoft estimates that less than 0.01% of users will be affected by this change. If your system relies on these legacy modems, they may stop functioning after installing KB5073724.
Updated Secure Boot Certificates
This update includes fresh Secure Boot certificates to replace expired ones. Secure Boot certificates are essential for:
- Verifying the integrity of boot components
- Protecting against rootkits and boot-level malware
- Maintaining system security during startup
This change is particularly crucial for enterprise environments running Windows 10 LTSC and ESU systems.
WinSqlite3.dll Security Enhancements
Microsoft has patched vulnerabilities in WinSqlite3.dll, a core Windows component. Some antivirus solutions were flagging applications using this library as potentially vulnerable.
If you encounter security warnings:
- Update all Microsoft Store apps
- For third-party applications using sqlite3.dll, contact the developer
- Ensure your antivirus definitions are current
Security Fixes in KB5073724
This Patch Tuesday update addresses 114 security vulnerabilities, including:
- 57 Elevation of Privilege vulnerabilities
- 22 Information Disclosure vulnerabilities
- 5 Spoofing vulnerabilities
- 3 zero-day exploits
One critical fix resolves a Desktop Window Manager vulnerability that allowed unauthorized actors to access local information and read memory addresses through a remote ALPC port exploit.
How to Download Windows 10 KB5073724
Ensure your system is eligible for ESU (enrolled in the ESU program). Without ESU enrolment, this update may not appear.
- Windows Update – Go to Settings > Update & Security > Windows Update and check for updates.
- Microsoft Update Catalog – You can manually download the standalone package from the Microsoft Update Catalog. (64-bit systems,ARM64 systems)
- Windows Server Update Services (WSUS) – For enterprise environments, KB5073724 will sync automatically if configured.
Windows 10 KB5073724 Direct Download Links:64-bit and 32-bit (x86).
Note: The link above to the Windows 10 offline installer opens Microsoft’s Update Catalog. You need to click on the “download” button next to the version of Windows 10 compatible with your system, and begin the download by clicking on .msu link which appears in the next pop-up.
If you are looking for the Windows 10 version 22H2 ISO you can get it from here.
Should You Install Windows 10 KB5073724?
Yes, absolutely. If you’re still running Windows 10, installing KB5073724 is essential for:
- Security protection – Patches critical vulnerabilities, including zero-day exploits
- System stability – Maintains compatibility with modern security protocols
- Compliance – Keeps enterprise systems within security standards
The update is particularly important for businesses that have purchased ESU licenses to extend Windows 10 support while planning their migration to Windows 11.
Frequently Asked Questions (FAQ)
No — this update is part of the ESU program. If you see it but aren’t enrolled, the install may fail or you may not receive future updates.
You can install it through Windows Update, Microsoft Update Catalog, or enterprise tools like WSUS.
No. This is a security-only update. No new OS features or enhancements are included.
Ensure you are connected to a stable internet connection, run the Windows Update troubleshooter, verify ESU enrolment, and consider a manual install via the Update Catalog.
