Vulnerability identifier: #VU53102

Vulnerability risk: Low

CVSSv3.1: 6.3 [CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-26422

CWE-ID: CWE-94

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Skype for Business Server
Server applications / Conferencing, Collaboration and VoIP solutions
Microsoft Lync
Client/Desktop applications / Messaging software

Vendor: Microsoft

Description

The vulnerability allows a remote user to execute arbitrary code on the target system.

The vulnerability exists due to improper input validation in Skype for Business and Lync. A remote administrator can execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Skype for Business Server: 2015 CU11 - 2019 CU5

Microsoft Lync:

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External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26422

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated privileged user via the Internet.

Is there known malware, which exploits this vulnerability?

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