Summary
This security update resolves vulnerabilities in Microsoft Skype for Business Server 2019. To learn more about these vulnerabilities, see the following security advisories:
- Skype for Business Spoofing Vulnerability CVE-2026-63523
- Skype for Business Information Disclosure Vulnerability CVE-2026-66304
- Skype for Business Denial of Service Vulnerability CVE-2026-66307
- Skype for Business Remote Code Execution Vulnerability CVE-2026-66302
- Skype for Business Denial of Service Vulnerability CVE-2026-66303
- Skype for Business Denial of Service Vulnerability CVE-2026-66308
- Skype for Business Spoofing Vulnerability CVE-2026-66305
- Skype for Business Information Disclosure Vulnerability CVE-2026-66306
- Skype for Business Spoofing Vulnerability CVE-2026-69642
- Skype for Business Spoofing Vulnerability CVE-2026-69646
Note
To apply this security update, you must have the release version of the following product installed:
Microsoft Skype for Business Server 2019
How to get and install the update
To get this update, install the following update:
Update for Skype for Business Server 2019
More information
Security update deployment information
For deployment information about this update, see Deployments - Security Update Guide.
How to get help and support for this security update
Protect yourself online: Windows Security support
Learn how we guard against cyber threats: Microsoft Security