CVE-2024-43491

Critical CVSS 9.8

Published 2024-09-10 · last changed 2026-06-17

The fix

Microsoft fixes this in updateKB5043083. The fixed build differs per Windows version, so the row that matters is the one matching the machine you are looking at.

Windows version	Fixed in build	Update	Released
Windows 10 for 32-bit Systems	10.0.10240.20766	KB5043083	2026-09-24
Windows 10 for x64-based Systems	10.0.10240.20766	KB5043083	2026-09-24

Having the KB is not the same as knowing whether a machine has it. Windows updates supersede each other, so the update you installed often covers a fix that shipped in an earlier one. Paste your build into the patch checker and it walks that chain for you.

What it is

Microsoft is aware of a vulnerability in Servicing Stack that has rolled back the fixes for some vulnerabilities affecting Optional Components on Windows 10, version 1507 (initial version released July 2015). This means that an attacker could exploit these previously mitigated vulnerabilities on Windows 10, version 1507 (Windows 10 Enterprise 2015 LTSB and Windows 10 IoT Enterprise 2015 LTSB) systems that have installed the Windows security update released on March 12, 2024—KB5035858 (OS Build 10240.20526) or other updates released until August 2024. All later versions of Windows 10 are not impacted by this vulnerability. This servicing stack vulnerability is addressed by installing the September 2024 Servicing stack update (SSU KB5043936) AND the September 2024 Windows security update (KB5043083), in that order. Note: Windows 10, version 1507 reached the end of support (EOS) on May 9, 2017 for devices running the Pro, Home, Enterprise, Education, and Enterprise IoT editions. Only Windows 10 Enterprise 2015 LTSB and Windows 10 IoT Enterprise 2015 LTSB editions are still under support.

Sources

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H