Detections
Analytics

Security Updates for Microsoft Excel Products C2R (January 2026)

high Nessus Plugin ID 283873

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Synopsis

The Microsoft Excel Products are missing a security update.

Description

The Microsoft Excel Products are missing a security update. It is, therefore, affected by the following vulnerabilities:

 - Multiple remote code execution vulnerabilities that attackers can exploit to bypass authentication and execute unauthorized arbitrary commands. (CVE-2026-20946, CVE-2026-20950, CVE-2026-20955, CVE-2026-20956, CVE-2026-20957)

 - A security feature bypass vulnerability. (CVE-2026-20949) Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Microsoft has released patches to address these issues.

For Office 365, Office 2016 C2R, or Office 2019, ensure automatic updates are enabled or open any office app and manually perform an update.

See Also

http://www.nessus.org/u?5931548c

Plugin Details

Severity: High

ID: 283873

File Name: smb_nt_ms26_jan_excel_c2r.nasl

Version: 1.2

Type: local

Agent: windows

Family: Windows

Published: 1/14/2026

Updated: 1/16/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: High

Base Score: 7.2

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-20957

CVSS v3

Risk Factor: High

Base Score: 7.8

Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Vulnerability Information

CPE: cpe:/a:microsoft:excel

Required KB Items: SMB/MS_Bulletin_Checks/Possible

Patch Publication Date: 1/13/2026

Vulnerability Publication Date: 1/13/2026

Reference Information

CVE: CVE-2026-20946, CVE-2026-20949, CVE-2026-20950, CVE-2026-20955, CVE-2026-20956, CVE-2026-20957

IAVA: 2026-A-0041