CVE-2026-21261
mediumpriority · track · 0EPSS 0.006 · 50 %ileDEEUNLRUUSEPSS · scored 2026-10-27
Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedMicrosoft 365 Apps for Enterprise for 32-bit Systemsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft 365 Apps for Enterprise for 64-bit Systemsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Excel 2016 (32-bit edition)msrc_csaf
16.0.5539.1002:Security Update:https://support.microsoft.com/help/5002837
https://support.microsoft.com/help/5002837 - FixedMicrosoft Excel 2016 (64-bit edition)msrc_csaf
16.0.5539.1002:Security Update:https://support.microsoft.com/help/5002837
https://support.microsoft.com/help/5002837 - FixedMicrosoft Office 2019 for 32-bit editionsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office 2019 for 64-bit editionsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office LTSC 2021 for 32-bit editionsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office LTSC 2021 for 64-bit editionsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office LTSC 2024 for 32-bit editionsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office LTSC 2024 for 64-bit editionsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office LTSC for Mac 2021msrc_csaf
16.106.26020821:Security Update:https://go.microsoft.com/fwlink/p/?linkid=831049
https://go.microsoft.com/fwlink/p/?linkid=831049 - FixedMicrosoft Office LTSC for Mac 2024msrc_csaf
16.106.26020821:Security Update:https://go.microsoft.com/fwlink/p/?linkid=831049
https://go.microsoft.com/fwlink/p/?linkid=831049 - FixedOffice Online Servermsrc_csaf
16.0.10417.20097:Security Update:https://support.microsoft.com/help/5002835
https://support.microsoft.com/help/5002835
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (86)
Products and version ranges known to be affected.
- Microsoft SharePoint Enterprise Server 2016all versionscert_bundDEcpe:/a:microsoft:sharepoint:enterprise_server_2016
- Microsoft SharePoint Server Subscription Editionall versionscert_bundDEcpe:/a:microsoft:sharepoint:server_subscription_edition
- Microsoft Microsoft 365 Apps for Enterprise16.0.1 → https://aka.ms/OfficeSecurityReleasesenisa_euvdEU
advisories (3)
Vendor and ecosystem advisories describing this.
- NCSC-2026-0058Kwetsbaarheden verholpen in Microsoft OfficeNL2026-02-10csaf · ncsc_nlNL
Microsoft heeft kwetsbaarheden verholpen in Office componenten.
- WID-SEC-W-2026-0371Microsoft Office: Mehrere SchwachstellenDeutsch2026-02-10csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Microsoft Excel, Microsoft Word, Microsoft Outlook, Microsoft Office Online Server, Microsoft SharePoint, Microsoft Office, Microsoft SharePoint Server 2019 und Microsoft 365 Apps ausnutzen, um Administratorrechte zu erlangen, Spoofing-Angriffe durchzuführen, Sicherheitsmaßnahmen zu umgehen und vertrauliche Informationen offenzulegen.
- msrc_CVE-2026-21261Microsoft Excel Information Disclosure Vulnerability2026-02-10csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (3)
External citations — patches, advisories, analysis.
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