Security Updates for Exchange (November 2021)

high Nessus Plugin ID 154999


The Microsoft Exchange Server installed on the remote host is affected by multiple vulnerabilities.


The Microsoft Exchange Server installed on the remote host is missing security updates. It is, therefore, affected by multiple vulnerabilities:

- A session spoofing vulnerability exists. An attacker can exploit this to perform actions with the privileges of another user. (CVE-2021-41349, CVE-2021-42305)

- A remote code execution vulnerability. An attacker can exploit this to bypass authentication and execute unauthorized arbitrary commands. (CVE-2021-42321)


Microsoft has released KB5007409 to address this issue.

See Also

Plugin Details

Severity: High

ID: 154999

File Name: smb_nt_ms21_nov_exchange.nasl

Version: 1.10

Type: local

Agent: windows

Published: 11/9/2021

Updated: 2/25/2022

Risk Information

CVSS Score Source: CVE-2021-42321


Risk Factor: Critical

Score: 9.6


Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

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

Temporal Vector: E:H/RL:OF/RC:C


Risk Factor: High

Base Score: 8.8

Temporal Score: 8.4

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

Temporal Vector: E:H/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:microsoft:exchange_server

Required KB Items: SMB/MS_Bulletin_Checks/Possible

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 11/9/2021

Vulnerability Publication Date: 11/9/2021

CISA Known Exploited Dates: 12/1/2021

Exploitable With

Metasploit (Microsoft Exchange Server ChainedSerializationBinder Deny List Typo RCE)

Reference Information

CVE: CVE-2021-41349, CVE-2021-42305, CVE-2021-42321

IAVA: 2021-A-0543-S

MSKB: 5007409

MSFT: MS21-5007409