High 7.5Published Feb 10, 2026

CVE-2026-21260Microsoft Outlook Spoofing Vulnerability

Updated under an hour ago (Oct 27, 2026, 10:23 PM ET)

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It affects Microsoft 365 Apps for Enterprise and 12 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

Exposure of sensitive information to an unauthorized actor in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
Weakness (CWE): CWE-200
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: microsoft
NVD analysis: Analyzed
Record last updated: Aug 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Microsoft Microsoft 365 Apps for Enterprise microsoft:365_apps_for_enterprise (from the name)	from 16.0.1 before https://aka.ms/OfficeSecurityReleases	CNA record
Microsoft Microsoft Office 2019 microsoft:office_2019 (from the name)	from 19.0.0 before https://aka.ms/OfficeSecurityReleases	CNA record
Microsoft Microsoft Office LTSC 2021 microsoft:office_ltsc_2021 (from the name)	from 16.0.1 before https://aka.ms/OfficeSecurityReleases	CNA record
Microsoft Microsoft Office LTSC 2024 microsoft:office_ltsc_2024 (from the name)	from 16.0.0 before https://aka.ms/OfficeSecurityReleases	CNA record
Microsoft Microsoft Outlook 2016 microsoft:outlook_2016 (from the name)	from 16.0.0.0 before 16.0.5539.1002	CNA record
Microsoft Microsoft SharePoint Enterprise Server 2016 microsoft:sharepoint_enterprise_server_2016 (from the name)	from 16.0.0 before 16.0.5539.1002	CNA record
Microsoft Microsoft SharePoint Server 2019 microsoft:sharepoint_server_2019 (from the name)	from 16.0.0 before 16.0.10417.20097	CNA record
Microsoft Microsoft SharePoint Server Subscription Edition microsoft:sharepoint_server_subscription_edition (from the name)	from 16.0.0 before 16.0.19127.20518	CNA record
microsoft 365_apps microsoft:365_apps	all versions; all versions	NVD
microsoft office microsoft:office	2019; 2019	NVD
1–10 of 13

References

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21260	vendor-advisory, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.