SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2026-44818

Concurrent execution using shared resource with improper synchronization ('race condition') in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

HIGH 7.0EPSS 0.26%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.26%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

CVSS 3.1
7.0 HIGHCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
0.26% probability · 18th percentile
CISA KEV
Not listed
Weakness
CWE-362
Affected
microsoft/365 apps · microsoft/excel · microsoft/microsoft 365 · microsoft/office 2019 · microsoft/office 2021 · microsoft/office 2024 · microsoft/office online server
Source
secure@microsoft.com

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.