A remote code execution vulnerability exists when Skype for Business and Microsoft Lync clients fail to properly sanitize specially crafted content. The vulnerability could corrupt memory in a way that could allow an attacker to execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, the attacker could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
An attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft Edge, and then convince a user to view the website. The attacker could also take advantage of compromised websites, or websites that accept or host user-provided content or advertisements, by adding specially crafted content that could exploit the vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically via an enticement in email or instant message, or by getting them to open an email attachment.
The security update addresses the vulnerability by modifying how Skype for Business and Lync clients sanitize content.
## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Microsoft | Microsoft Lync 2013 Service Pack 1 (32-bit) | | [KB4022225](https://patchblox.com/security/data/fix/microsoft/kb4022225.md) | Jul 10, 2018 | | Microsoft | Microsoft Lync 2013 Service Pack 1 (64-bit) | | [KB4022225](https://patchblox.com/security/data/fix/microsoft/kb4022225.md) | Jul 10, 2018 | | Microsoft | Skype for Business 2016 (32-bit) | | [KB4022221](https://patchblox.com/security/data/fix/microsoft/kb4022221.md) | Jul 10, 2018 | | Microsoft | Skype for Business 2016 (64-bit) | | [KB4022221](https://patchblox.com/security/data/fix/microsoft/kb4022221.md) | Jul 10, 2018 | --- Data as of 2026-11-09T13:31:49Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.