Unrated severityNVD Advisory· Published Feb 10, 2026· Updated Apr 10, 2026
Microsoft Outlook Spoofing Vulnerability
CVE-2026-21511
Description
Deserialization of untrusted data in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network.
Affected products
11- Microsoft/Microsoft 365 Apps for Enterprisev5Range: 16.0.1
- Microsoft/Microsoft Office 2019v5Range: 19.0.0
- Microsoft/Microsoft Office LTSC 2021v5Range: 16.0.1
- Microsoft/Microsoft Office LTSC 2024v5Range: 16.0.0
- Microsoft/Microsoft Office LTSC for Mac 2021v5Range: 16.0.1
- Microsoft/Microsoft Office LTSC for Mac 2024v5Range: 16.0.0
- Microsoft/Microsoft SharePoint Enterprise Server 2016v5Range: 16.0.0
- Microsoft/Microsoft SharePoint Server 2019v5Range: 16.0.0
- Microsoft/Microsoft SharePoint Server Subscription Editionv5Range: 16.0.0
- Microsoft/Microsoft Word 2016v5Range: 16.0.1
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
1- msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21511mitrevendor-advisorypatch
News mentions
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