CVE-2026-40420
published 2026-05-12CVE-2026-40420: Use after free in Microsoft Office allows an authorized attacker to elevate privileges locally.
PriorityP349high8.8CVSS 3.1
AVLACLPRLUINSCCHIHAH
EPSS
0.21%
11.6th percentile
Use after free in Microsoft Office allows an authorized attacker to elevate privileges locally.
Affected
7 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | microsoft_365_apps_for_enterprise | >= 16.0.1 < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| microsoft | microsoft_office_2019 | >= 19.0.0 < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| microsoft | microsoft_office_ltsc_2021 | >= 16.0.1 < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| microsoft | microsoft_office_ltsc_2024 | >= 16.0.0 < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| microsoft | office | — | — |
| microsoft | office_long_term_servicing_channel | — | — |
| microsoft | office_long_term_servicing_channel | — | — |
Stop checking back — get the weekly exploitation signal.
Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.
GHSA
GHSA-q3w4-cjqg-q4x3: Improper access control in Microsoft Office Click-To-Run allows an authorized attacker to elevate privileges locally
ghsa_unreviewed·2026-05-12
CVE-2026-40420 [HIGH] CWE-284 GHSA-q3w4-cjqg-q4x3: Improper access control in Microsoft Office Click-To-Run allows an authorized attacker to elevate privileges locally
Improper access control in Microsoft Office Click-To-Run allows an authorized attacker to elevate privileges locally.
VulDB
Microsoft Office 365 Apps/2019/LTSC 2021/LTSC 2024 access control
vuldb·2026-05-12
CVE-2026-40420 [CRITICAL] Microsoft Office 365 Apps/2019/LTSC 2021/LTSC 2024 access control
A vulnerability was found in Microsoft Office 2019/365 Apps/LTSC 2021/LTSC 2024 and classified as critical. This affects an unknown function. Such manipulation leads to improper access controls.
This vulnerability is documented as CVE-2026-40420. The attack needs to be performed locally. There is not any exploit available.
It is best practice to apply a patch to resolve this issue.
No detection rules found.
No public exploits indexed.
2026-05-12
Published