Cyber Resilience

CVE-2026-40415

High

Published: 12 May 2026

Published
12 May 2026
Modified
15 May 2026
KEV Added
—
Patch
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CVSS Score v3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0079 51.7th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-40415 is a high-severity Use After Free (CWE-416) vulnerability in Microsoft Windows 10 21H2. Its CVSS base score is 8.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 48.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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

CWE(s)
CWE-416

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
Why these techniques?

UAF in Windows TCP/IP stack directly enables remote code execution by an unauth attacker over the network, mapping to exploitation of remote/public-facing services.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-33835Same product: Microsoft Windows 10 1809
CVE-2026-32078Same product: Microsoft Windows 10 1809
CVE-2026-24292Same product: Microsoft Windows 10 1809
CVE-2026-23669Same product: Microsoft Windows 10 1809
CVE-2025-62221Same product: Microsoft Windows 10 1809
CVE-2026-20923Same product: Microsoft Windows 10 1809
CVE-2026-20865Same product: Microsoft Windows 10 1809
CVE-2026-33098Same product: Microsoft Windows 10 1809
CVE-2025-21224Same product: Microsoft Windows 10 21H2
CVE-2026-26132Same product: Microsoft Windows 10 21H2

Affected Assets

microsoft
windows 10 1809
≤ 10.0.17763.8755 · ≤ 10.0.17763.8755
microsoft
windows 10 21h2
≤ 10.0.19044.7291 · ≤ 10.0.19044.7291 · ≤ 10.0.19044.7291
microsoft
windows 10 22h2
≤ 10.0.19045.7291 · ≤ 10.0.19045.7291 · ≤ 10.0.19045.7291
microsoft
windows 11 23h2
≤ 10.0.22631.7079 · ≤ 10.0.22631.7079
microsoft
windows 11 24h2
≤ 10.0.26100.8390 · ≤ 10.0.26100.8390
microsoft
windows 11 25h2
≤ 10.0.26200.8390 · ≤ 10.0.26200.8390
microsoft
windows 11 26h1
≤ 10.0.28000.2113 · ≤ 10.0.28000.2113
microsoft
windows server 2019
≤ 10.0.17763.8755
microsoft
windows server 2022
≤ 10.0.20348.5074
microsoft
windows server 2022 23h2
≤ 10.0.25398.2330
+1 more product configuration(s) — see NVD for full list

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SI-16 Memory Protection
addresses: CWE-416

Use-after-free exploits that achieve arbitrary code execution are blocked or significantly hardened by non-executable pages and ASLR.

References