SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-55138

Untrusted pointer dereference in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

MEDIUM 5.5EPSS 0.54%

Does this matter?

Lower severity and a low EPSS score (0.54%). Track it; it rarely justifies an emergency change on its own.

Description

Untrusted pointer dereference in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

CVSS 3.1
5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
EPSS
0.54% probability · 44th percentile
CISA KEV
Not listed
Weakness
CWE-822
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.