CVE-2026-66304

highpriority · track · 0EPSS 0.010 · 62 %ileDENLRUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.97% (62nd) EPSS

CVSS 7.5 · high

Is it mine?

57 products

Check your exposure

Who says so?

4 sources

fstec_bdu · cert_bund · ncsc_nl · msrc_csaf

EPSS · scored 2026-10-27

Server-side request forgery (ssrf) in Skype for Business allows an unauthorized attacker to disclose information over a network.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedSkype for Business Server 2015 CU13msrc_csaf
6.0.9319.885:Security Update:https://support.microsoft.com/help/5123301
https://support.microsoft.com/help/5123301
FixedSkype for Business Server 2019 CU8msrc_csaf
7.0.2046.569:Security Update:https://support.microsoft.com/help/5123300
https://support.microsoft.com/help/5123300
FixedSkype for Business Server Subscription Edition CU1msrc_csaf
7.0.2046.879:Security Update:https://support.microsoft.com/help/5123287
https://support.microsoft.com/help/5123287

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–7.5

v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nsecondary · FSTEC (BDU) RU

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nsecondary · secure@microsoft.com USexploitability 3.9 · impact 3.6

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:Csecondary · Microsoft Security Response Center US

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-918USCWE-918USCWE-918US

affected products (57)

Products and version ranges known to be affected.

Microsoft 365 Appsall versionscert_bundDEcpe:/a:microsoft:365_apps:-
Microsoft Access 2016all versionscert_bundDEcpe:/a:microsoft:access:2016
Microsoft Excel 2016all versionscert_bundDEcpe:/a:microsoft:excel:2016
Microsoft Office 2016all versionscert_bundDEcpe:/a:microsoft:office:2016
Microsoft Office 2019all versionscert_bundDEcpe:/a:microsoft:office:2019
Microsoft Office 365 for Macall versionscert_bundDEcpe:/a:microsoft:office_365:for_mac
Microsoft Office LTSC 2021all versionscert_bundDEcpe:/a:microsoft:office:ltsc_2021
Microsoft Office LTSC 2024all versionscert_bundDEcpe:/a:microsoft:office:ltsc_2024
Microsoft Office LTSC for Mac 2021all versionscert_bundDEcpe:/a:microsoft:office:ltsc_for_mac_2021
Microsoft Office LTSC for Mac 2024all versionscert_bundDEcpe:/a:microsoft:office:ltsc_for_mac_2024
Microsoft Office Online Serverall versionscert_bundDEcpe:/a:microsoft:office_online_server:-
Microsoft Office for Androidall versionscert_bundDEcpe:/a:microsoft:office:for_android
Microsoft Outlook 2016all versionscert_bundDEcpe:/a:microsoft:outlook:2016
Microsoft PowerPoint 2016all versionscert_bundDEcpe:/a:microsoft:powerpoint:2016
Microsoft SharePoint Server Subscription Editionall versionscert_bundDEcpe:/a:microsoft:sharepoint:server_subscription_edition
Microsoft Skype for Business Server 2015 CU13all versionscert_bundDEcpe:/a:microsoft:skype:for_business_server_2015_cu13
Microsoft Skype for Business Server 2019 CU8all versionscert_bundDEcpe:/a:microsoft:skype:for_business_server_2019_cu8
Microsoft Skype for Business Server Subscription Edition CU1all versionscert_bundDEcpe:/a:microsoft:skype:for_business_server_subscription_edition_cu1
Microsoft Teams for Androidall versionscert_bundDEcpe:/a:microsoft:teams:for_android
Microsoft Word 2016all versionscert_bundDEcpe:/a:microsoft:word:2016

showing 20 of 57

advisories (3)

Vendor and ecosystem advisories describing this.

NCSC-2026-0352Kwetsbaarheden verholpen in Microsoft OfficeNL2026-09-08csaf · ncsc_nlNL
Microsoft heeft 114 kwetsbaarheden verholpen in diverse Office producten.
WID-SEC-W-2026-3234Microsoft Office Produkte: Mehrere SchwachstellenDeutsch2026-09-08csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in verschiedenen Microsoft Office Produkten, Microsoft Office Online Server, Microsoft 365 Apps, Microsoft SharePoint, Microsoft Teams und Microsoft Skype ausnutzen, um erhöhte Berechtigungen zu erlangen, um Code auszuführen, um Informationen offenzulegen und um den Nutzer zu täuschen.
msrc_CVE-2026-66304Skype for Business Information Disclosure Vulnerability2026-09-08csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

also known as (1)

Other names and identifiers for this entity.

BDU:2026-14845 fstec_bdu

sources

Which sources assert this record, and when.

fstec_bdu cert_bund ncsc_nl msrc_csaf NVD CVE.org MITRE

published 2026-09-08modified 2026-09-18

references (1) nvd

External citations — patches, advisories, analysis.

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66304PatchVendor Advisory

scry

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