Skype for Business Spoofing Vulnerability

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-66305
StatePUBLISHED
Assignermicrosoft
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-08 19:18:08 UTC
Updated2026-09-09 17:17:26 UTC
DescriptionUse of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network.

Risk And Classification

Primary CVSS: v3.1 7.1 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N

EPSS: 0.003020000 probability, percentile 0.226800000 (date 2026-09-09)

Problem Types: CWE-603 | CWE-603 CWE-603: Use of Client-Side Authentication

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.1HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N
3.1CNACVSS7.1HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N/E:U/RL:O/RC:C

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Microsoft Skype For Business Server 2015 CU13 affected 9319.0 6.0.9319.885 custom x64-based Systems
CNA Microsoft Skype For Business Server 2019 CU8 affected 2046.0 7.0.2046.569 custom x64-based Systems
CNA Microsoft Skype For Business Server Subscription Edition CU1 affected 2046.0 7.0.2046.879 custom x64-based Systems

References

ReferenceSourceLinkTags
msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66305 [email protected] msrc.microsoft.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report