CVE-2026-40415 — Windows TCP/IP Remote Code Execution Vulnerability

Executive Summary

Use after free in Windows TCP/IP allows an unauthorized attacker to execute code over a network.

Overview

8.1

CVSS HIGH

Important

MS Severity

Not Exploited

MS Exploit Status

Exploitation Unlikely

MS Exploit Likelihood

Category Remote Code Execution

Released May 12 2026

Last Updated May 12 2026

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.00789 — 0.51413 percentile

NVD CVSS 8.1 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

ATTACK VECTOR

Network

ATTACK COMPLEXITY

High

PRIVILEGES REQUIRED

None

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

High

AVAILABILITY

High

EXPLOIT CODE MATURITY

Unproven

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 7.1

EPSS Score

0.00789

probability of exploitation in the next 30 days

0.51413 percentile - updated 2026-06-21

View on FIRST.org

Affected Products

15 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1809 for 32-bit Systems	`5087538 (Security Update)`	Important	Remote Code Execution	Yes
Windows 10 Version 1809 for x64-based Systems	`5087538 (Security Update)`	Important	Remote Code Execution	Yes
Windows 10 Version 21H2 for 32-bit Systems	`5087544 (Security Update)`	Important	Remote Code Execution	Yes
Windows 10 Version 21H2 for ARM64-based Systems	`5087544 (Security Update)`	Important	Remote Code Execution	Yes
Windows 10 Version 21H2 for x64-based Systems	`5087544 (Security Update)`	Important	Remote Code Execution	Yes
Windows 10 Version 22H2 for 32-bit Systems	`5094127 (Security Update)`	Important	Remote Code Execution	Yes
Windows 10 Version 22H2 for ARM64-based Systems	`5094127 (Security Update)`	Important	Remote Code Execution	Yes
Windows 10 Version 22H2 for x64-based Systems	`5094127 (Security Update)`	Important	Remote Code Execution	Yes
Windows 11 Version 23H2 for ARM64-based Systems	`5087420 (Security Update)`	Important	Remote Code Execution	Yes
Windows 11 Version 23H2 for x64-based Systems	`5093998 (Security Update)`	Important	Remote Code Execution	Yes
Windows 11 Version 24H2 for ARM64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Important Remote Code Execution 5082063 Base: 8.1 Temporal: 7.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.8457 10.0.26100.8390 Yes None Windows 11 Version 24H2 for x64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Important Remote Code Execution 5082063 Base: 8.1 Temporal: 7.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.8457 10.0.26100.8390 Yes None Windows 11 Version 25H2 for ARM64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Important Remote Code Execution 5083769 Base: 8.1 Temporal: 7.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26200.8457 10.0.26200.8390 Yes None Windows 11 Version 25H2 for x64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Important Remote Code Execution 5083769 Base: 8.1 Temporal: 7.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26200.8457 10.0.26200.8390 Yes None Windows 11 Version 26H1 for ARM64-based Systems	`5089548 (Security Update)`	Important	Remote Code Execution	Yes
Windows 11 version 26H1 for x64-based Systems	`5089548 (Security Update)`	Important	Remote Code Execution	Yes
Windows Server 2019	`5087538 (Security Update)`	Important	Remote Code Execution	Yes
Windows Server 2019 (Server Core installation)	`5087538 (Security Update)`	Important	Remote Code Execution	Yes
Windows Server 2022 5087545 (Security Update) 5087424 (Security Hotpatch Update) Important Remote Code Execution 5082142 Base: 8.1 Temporal: 7.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.20348.5139 10.0.20348.5074 Yes None Windows Server 2022 (Server Core installation) 5087545 (Security Update) 5087424 (Security Hotpatch Update) Important Remote Code Execution 5082142 Base: 8.1 Temporal: 7.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.20348.5139 10.0.20348.5074 Yes None Windows Server 2022, 23H2 Edition (Server Core installation)	`5087541 (Security Update)`	Important	Remote Code Execution	Yes

Patches

7 patches

Article	Type	Restart
`5087538`	Security Update	Yes
`5087544`	Security Update	Yes
`5094127`	Security Update	Yes
`5087420`	Security Update	Yes
`5093998`	Security Update	Yes
`5089548`	Security Update	Yes
`5087541`	Security Update	Yes

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

Microsoft

References

MSRC Advisory MITRE NVD