VIR Vulnerability Intelligence Relay

CVE-2026-40420

high
Published 2026-05-12 · Modified 2026-05-19
CVSS v3
8.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS v2
—
VIR risk
8.8

Description

Improper access control in Microsoft Office Click-To-Run allows an authorized attacker to elevate privileges locally.

Predictions

Exploit likelihood
82%
Patch ETA
—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: secure@microsoft.com — https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40420

Application impact
VendorProductVersionsFixed
windows microsoft365_apps-
windows microsoftoffice2019
windows microsoftoffice_long_term_servicing_channel2021
windows microsoftoffice_long_term_servicing_channel2024

References

CWEs

CWE-284

Verify integrity in audit chain (admin only). AS-IS.