#VU53082 Improper validation of integrity check value in Microsoft Exchange Server

Published: 2021-05-11 | Updated: 2021-06-01

Vulnerability identifier: #VU53082

Vulnerability risk: Medium

CVSSv3.1: 7.7 [CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-31209


Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
Microsoft Exchange Server
Server applications / Mail servers

Vendor: Microsoft


The vulnerability allows a remote attacker to bypass integrity checks.

The vulnerability exists within the handling of Exchange Server Help updates. A remote attacker on the local network can bypass integrity check on update downloads.

Install updates from vendor's website.

Vulnerable software versions

Microsoft Exchange Server: 2013 Cumulative Update 23 15.00.1497.002, 2019 Cumulative Update 8 15.02.0792.003 - 2019 Cumulative Update 9 15.02.0858.005, 2016 Cumulative Update 19 15.01.2176.002 - 2016 Cumulative Update 20 15.01.2242.004

External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

Latest bulletins with this vulnerability