CVE-2026-34340

Published: May 12, 2026Modified: Jun 17, 2026

7.0

Vector

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

Exploitability: 1.0 / Impact: 5.9

Source: secure@microsoft.com (Secondary)

Description

Use after free in Windows Projected File System allows an authorized attacker to elevate privileges locally.

Affected (20)

Products: Microsoft: Windows 10 1809, Windows 10 21h2, Windows 10 22h2, Windows 11 23h2, Windows 11 24h2, Windows 11 25h2, Windows 11 26h1, Windows Server 2019, Windows Server 2022, Windows Server 2022 23h2, Windows Server 2025

11 products

Windows 10 1809

Windows 10 21h2

Windows 10 22h2

Windows 11 23h2

Windows 11 24h2

Windows 11 25h2

Windows 11 26h1

Windows Server 2019

Windows Server 2022

Windows Server 2022 23h2

Windows Server 2025

Configuration A

20 vulnerable

Vulnerable Software	Affected Versions
Microsoft Windows 10 1809	version < 10.0.17763.8755
Microsoft Windows 10 1809	version < 10.0.17763.8755
Microsoft Windows 10 21h2	version < 10.0.19044.7291
Microsoft Windows 10 21h2	version < 10.0.19044.7291
Microsoft Windows 10 21h2	version < 10.0.19044.7291
Microsoft Windows 10 22h2	version < 10.0.19045.7291
Microsoft Windows 10 22h2	version < 10.0.19045.7291
Microsoft Windows 10 22h2	version < 10.0.19045.7291
Microsoft Windows 11 23h2	version < 10.0.22631.7079
Microsoft Windows 11 23h2	version < 10.0.22631.7079
Microsoft Windows 11 24h2	version < 10.0.26100.8390
Microsoft Windows 11 24h2	version < 10.0.26100.8390
Microsoft Windows 11 25h2	version < 10.0.26200.8390
Microsoft Windows 11 25h2	version < 10.0.26200.8390
Microsoft Windows 11 26h1	version < 10.0.28000.2113
Microsoft Windows 11 26h1	version < 10.0.28000.2113
Microsoft Windows Server 2019	version < 10.0.17763.8755
Microsoft Windows Server 2022	version < 10.0.20348.5074
Microsoft Windows Server 2022 23h2	version < 10.0.25398.2330
Microsoft Windows Server 2025	version < 10.0.26100.32772

Related CWEs

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34340

Source: secure@microsoft.com

Vendor Advisory

Timeline

No history available yet.