# CVE-2019-0798: Skype for Business and Lync Spoofing Vulnerability

CVE-2019-0798 is fixed in 2 products on 1 platform, first by KB2809243, released March 12, 2019. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2019-0798
- Priority: High
- CVSS: n/a (Important)
- EPSS: 0.0208
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Mar 12, 2019
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2019-0798

## Description

<p>A spoofing vulnerability exists when a Lync Server or Skype for Business Server does not properly sanitize a specially crafted request. An authenticated attacker could exploit the vulnerability by sending a specially crafted request to an affected server. The attacker who successfully exploited this vulnerability could then perform cross-site scripting attacks on affected systems and run script in the security context of the current user.</p> <p>For the vulnerability to be exploited, a user must click a specially crafted URL that takes the user to a targeted Lync or Skype for Business site.</p> <p>In an email attack scenario, an attacker could exploit the vulnerability by sending an email message containing the specially crafted URL to the user of the targeted Lync or Skype for Business site and convincing the user to click the specially crafted URL.</p> <p>The security update addresses the vulnerability by helping to ensure that Lync Server and Skype for Business Server properly sanitize web requests.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Microsoft Lync Server 2013 July 2018 Update |  | [KB2809243](https://patchblox.com/security/data/fix/microsoft/kb2809243.md) | Mar 12, 2019 |
| Microsoft | Skype for Business Server 2015 March 2019 Update |  | [KB3061064](https://patchblox.com/security/data/fix/microsoft/kb3061064.md) | Oct 10, 2023 |

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