CVE-2026-66305: Skype for Business Spoofing Vulnerability

Published Sep 8, 2026
·
Updated

Skype for Business Spoofing Vulnerability

Other sources

Use of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network.

Microsoft

Affected Software

3 affected componentsFixes available
Microsoft Skype for Business Server 2015 CU13<6.0.9319.885
6.0.9319.885
Microsoft Skype for Business Server 2019 CU8<7.0.2046.569
7.0.2046.569
Microsoft Skype for Business Server Subscription Edition CU1<7.0.2046.879
7.0.2046.879

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 7.0.2046.569Patch KB5123300
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.0.9319.885Patch KB5123301
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 7.0.2046.879Patch KB5123287

Event History

Sep 8, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Description
CVE Published
via MITRE·06:32 PM
Data Sourced
via MITRE·06:32 PM
DescriptionSeverity
Data Sourced
via NVD·07:18 PM
DescriptionSeverityWeakness

Frequently Asked Questions

1

Which deployments are identified as affected?

The affected software listed is Microsoft Skype for Business Server 2015 CU13, Skype for Business Server 2019 CU8, and Skype for Business Server Subscription Edition CU1.

2

What access does an attacker need to exploit this issue?

The attacker must be authorized and able to act over a network. The provided information does not indicate that user interaction is required.

Contact

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