CVE-2026-21253

Mailslot File System Elevation of Privilege Vulnerability

State: Published
Severity: 7.0 High
Published: Feb 10, 2026
Updated: Aug 19, 2026
Reserved: Dec 11, 2025

Description

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

Scores

CVSS	Score	Vector	Source
3.1	7.0 High	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C	microsoft

Weaknesses

CWE-416 Use After Free

Affected Products

Product	Versions
Windows 10 Version 1607Microsoft	10.0.14393.0 to before 10.0.14393.8868Affected
Windows 10 Version 1809Microsoft	10.0.17763.0 to before 10.0.17763.8389Affected
Windows 10 Version 21H2Microsoft	10.0.19044.0 to before 10.0.19044.6937Affected
Windows 10 Version 22H2Microsoft	10.0.19045.0 to before 10.0.19045.6937Affected
Windows 11 version 22H3Microsoft	10.0.22631.0 to before 10.0.22631.6649Affected
Windows 11 Version 23H2Microsoft	10.0.22631.0 to before 10.0.22631.6649Affected
Windows 11 Version 24H2Microsoft	10.0.26100.0 to before 10.0.26100.7840Affected
Windows 11 Version 25H2Microsoft	10.0.26200.0 to before 10.0.26200.7840Affected
Windows 11 version 26H1Microsoft	10.0.28000.0 to before 10.0.28000.1575Affected
Windows 11 Version 26H1Microsoft	10.0.28000.0 to before 10.0.28000.1575Affected
Windows Server 2012Microsoft	6.2.9200.0 to before 6.2.9200.25923Affected
Windows Server 2012 (Server Core installation)Microsoft	6.2.9200.0 to before 6.2.9200.25923Affected
Windows Server 2012 R2Microsoft	6.3.9600.0 to before 6.3.9600.23022Affected
Windows Server 2012 R2 (Server Core installation)Microsoft	6.3.9600.0 to before 6.3.9600.23022Affected
Windows Server 2016Microsoft	10.0.14393.0 to before 10.0.14393.8868Affected
Windows Server 2016 (Server Core installation)Microsoft	10.0.14393.0 to before 10.0.14393.8868Affected
Windows Server 2019Microsoft	10.0.17763.0 to before 10.0.17763.8389Affected
Windows Server 2019 (Server Core installation)Microsoft	10.0.17763.0 to before 10.0.17763.8389Affected
Windows Server 2022Microsoft	10.0.20348.0 to before 10.0.20348.4773Affected
Windows Server 2022, 23H2 Edition (Server Core installation)Microsoft	10.0.25398.0 to before 10.0.25398.2149Affected
Windows Server 2025Microsoft	10.0.26100.0 to before 10.0.26100.32370Affected
Windows Server 2025 (Server Core installation)Microsoft	10.0.26100.0 to before 10.0.26100.32370Affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.