Privilege escalation in Microsoft Lync

Published: 2017-10-10 | Updated: 2017-10-11
Risk Low
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2017-11786
Exploitation vector Network
Public exploit N/A
Vulnerable software
Microsoft Lync
Client/Desktop applications / Messaging software

Vendor Microsoft

Security Bulletin

This security bulletin contains one low risk vulnerability.

1) Privilege escalation


Risk: Low

CVSSv3.1: 5.5 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-11786

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No


The vulnerability allows a remote authenticated attacker to gain elevated privileges on the target system.

The weakness exists due to when Skype for Business fails to properly handle specific authentication requests. A remote attacker can invite a user to an instant message session while using a malicious profile image, steal an authentication has and gain system privileges.


Install updates from vendor's website.

Vulnerable software versions

Microsoft Lync: 2013

CPE2.3 External links

Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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