Microsoft security update for CVE-2026-21511
🔗 CVE IDs covered (1)
📋 Microsoft's advisory
EchelonGraph does not copy Microsoft's advisory page: its FAQ and remediation text are not shown here. Read the advisory on https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21511. This page also shows what EchelonGraph holds for CVE-2026-21511, with the description from its CVE record, which the CVE Numbering Authority that assigned the CVE wrote: for a CVE Microsoft assigned, often in the words of Microsoft's own advisory.
🎯 Affected products15
- Microsoft 365 Apps for Enterprise for 32-bit Systems
- Microsoft 365 Apps for Enterprise for 64-bit Systems
- Microsoft Office 2019 for 32-bit editions
- Microsoft Office 2019 for 64-bit editions
- Microsoft Office LTSC 2021 for 32-bit editions
- Microsoft Office LTSC 2021 for 64-bit editions
- Microsoft Office LTSC 2024 for 32-bit editions
- Microsoft Office LTSC 2024 for 64-bit editions
- Microsoft Office LTSC for Mac 2021
- Microsoft Office LTSC for Mac 2024
- Microsoft SharePoint Enterprise Server 2016
- Microsoft SharePoint Server 2019
- Microsoft SharePoint Server Subscription Edition
- Microsoft Word 2016 (32-bit edition)
- Microsoft Word 2016 (64-bit edition)
✅ Updates Microsoft lists: 8 updates
8 rows: one per KB article or update, update type and fixed build. Their details are on Microsoft's advisory.
| KB article | Update | Fixed build |
|---|---|---|
| — | Security Update | 16.0.5539.1002 |
| — | Security Update | 16.0.5539.1002 |
| — | Security Update | 16.0.10417.20097 |
| — | Security Update | 16.0.10417.20097 |
| — | Security Update | release notes |
| — | Security Update | 16.106.26020821 |
| — | Security Update | 16.0.19127.20518 |
| — | Security Update | 16.0.5539.1002 |
🧭 EchelonGraph on CVE-2026-21511
- EchelonGraph score
- 7.5 HIGH
- CISA KEV
- Not listed
- Fix status
- A fix is available — apply it.
Description from the CVE record (CVE.org), as published by its numbering authority
Deserialization of untrusted data in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network.
Published by Microsoft Corporation, the CVE Numbering Authority that assigned CVE-2026-21511, in its CVE record at CVE.org; reused under the CVE Program's Terms of Use (its licence and MITRE's copyright notice are in our Terms of Service).
🔗 References (15)
- advisoryhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21511
- patchhttps://www.microsoft.com/en-us/download/details.aspx?id=108550
- referencehttps://support.microsoft.com/help/5002841
- patchhttps://www.microsoft.com/en-us/download/details.aspx?id=108553
- referencehttps://support.microsoft.com/help/5002840
- patchhttps://www.microsoft.com/en-us/download/details.aspx?id=108549
- referencehttps://support.microsoft.com/help/5002834
- patchhttps://www.microsoft.com/en-us/download/details.aspx?id=108552
- referencehttps://support.microsoft.com/help/5002836
- referencehttps://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
- patchhttps://go.microsoft.com/fwlink/p/?linkid=831049
- patchhttps://www.microsoft.com/en-us/download/details.aspx?id=108554
- referencehttps://support.microsoft.com/help/5002833
- patchhttps://www.microsoft.com/en-us/download/details.aspx?id=108548
- referencehttps://support.microsoft.com/help/5002839