Detections
Analytics

Security Updates for Microsoft Exchange Server (October 2026 OOB)

high Nessus Plugin ID 363841

Synopsis

The Microsoft Exchange Server installed on the remote host is affected by an elevation of privilege vulnerability.

Description

The Microsoft Exchange Server installed on the remote host is missing a security update. It is, therefore, affected by an elevation of privilege vulnerability:

 - Weak authorization in Microsoft Exchange Server allows an authenticated attacker to elevate privileges over a network. (CVE-2026-96940)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Microsoft has released the following security updates to address this issue:
 -KB5129955
 -KB5129956
 -KB5129957
 -KB5129958

See Also

https://support.microsoft.com/help/5129955

https://support.microsoft.com/help/5129956

https://support.microsoft.com/help/5129957

https://support.microsoft.com/help/5129958

Plugin Details

Severity: High

ID: 363841

File Name: smb_nt_ms26_oct_exchange_oob.nasl

Version: 1.1

Type: Local

Agent: windows

Published: 10/7/2026

Updated: 10/7/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.9

Percentile: 99.35

CVSS v2

Risk Factor: High

Base Score: 9

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

CVSS Score Source: CVE-2026-96940

CVSS v3

Risk Factor: High

Base Score: 8.8

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

Vulnerability Information

CPE: cpe:/a:microsoft:exchange_server:2016, cpe:/a:microsoft:exchange_server:2019, cpe:/a:microsoft:exchange_server:subscription_edition

Required KB Items: SMB/MS_Bulletin_Checks/Possible

Patch Publication Date: 10/2/2026

Vulnerability Publication Date: 10/2/2026

Reference Information

CVE: CVE-2026-96940

CWE: 1390

MSFT: MS26-5129955, MS26-5129956, MS26-5129957, MS26-5129958

MSKB: 5129955, 5129956, 5129957, 5129958