Cyber Resilience

CVE-2026-40418

HighUpdated

Published: 12 May 2026

Published
12 May 2026
Modified
01 June 2026
KEV Added
Patch
CVSS Score v3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0005 15.7th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-40418 is a high-severity Use After Free (CWE-416) vulnerability in Microsoft Office Long Term Servicing Channel. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 15.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Use after free in Microsoft Office allows an authorized attacker to elevate privileges locally.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

UAF vulnerability in local Office component directly enables local privilege escalation via exploitation of the flaw (T1068).

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

CVEs Like This One

CVE-2026-40419Same product: Microsoft 365 Apps
CVE-2026-20953Same product: Microsoft 365 Apps
CVE-2025-54910Same product: Microsoft 365 Apps
CVE-2026-40420Same product: Microsoft 365 Apps
CVE-2025-24080Same product: Microsoft 365 Apps
CVE-2025-21392Same product: Microsoft 365 Apps
CVE-2025-53740Same product: Microsoft 365 Apps
CVE-2026-20952Same product: Microsoft 365 Apps
CVE-2025-53731Same product: Microsoft 365 Apps
CVE-2025-21345Same product: Microsoft 365 Apps

Affected Assets

microsoft
365 apps
all versions
microsoft
office
2019
microsoft
office long term servicing channel
2021, 2024

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.

addresses: CWE-416

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

References