CVE-2026-21261

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

CVSS v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21261	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:microsoft:365_apps:-::::enterprise::x64:*
	cpe:2.3:a:microsoft:365_apps:-::::enterprise::x86:*
	cpe:2.3:a:microsoft:excel:2016::::::x64:
	cpe:2.3:a:microsoft:excel:2016::::::x86:
	cpe:2.3:a:microsoft:office:2019::::::x64:
	cpe:2.3:a:microsoft:office:2019::::::x86:
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:::::macos::
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024::::::x64:
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024::::::x86:
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::-:x64:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::-:x86:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::macos::
	cpe:2.3:a:microsoft:office_online_server::::::::

History

No history.

Information

Published : 2026-02-10 18:16

Updated : 2026-06-17 10:18

NVD link : CVE-2026-21261

Mitre link : CVE-2026-21261

CVE.ORG link : CVE-2026-21261

JSON object : View

Products Affected

microsoft

office
office_long_term_servicing_channel
excel
365_apps
office_online_server

CWE

CWE-125

Out-of-bounds Read

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"affected", "version": "16.0.1", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom"}], "platforms": ["32-bit Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Microsoft Excel 2016", "versions": [{"status": "affected", "version": "16.0.0.0", "lessThan": "16.0.5539.1002", "versionType": "custom"}], "platforms": ["32-bit Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Microsoft Office 2019", "versions": [{"status": "affected", "version": "19.0.0", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom"}], "platforms": ["32-bit Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC 2021", "versions": [{"status": "affected", "version": "16.0.1", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom"}], "platforms": ["32-bit Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC 2024", "versions": [{"status": "affected", "version": "16.0.0", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom"}], "platforms": ["32-bit Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC for Mac 2021", "versions": [{"status": "affected", "version": "16.0.1", "lessThan": "16.106.26020821", "versionType": "custom"}]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC for Mac 2024", "versions": [{"status": "affected", "version": "16.0.0", "lessThan": "16.106.26020821", "versionType": "custom"}]}, {"vendor": "Microsoft", "product": "Office Online Server", "versions": [{"status": "affected", "version": "16.0.0.0", "lessThan": "16.0.10417.20097", "versionType": "custom"}]}]}], "published": "2026-02-10T18:16:28.107", "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21261", "tags": ["Vendor Advisory"], "source": "secure@microsoft.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "secure@microsoft.com", "description": [{"lang": "en", "value": "CWE-125"}]}], "descriptions": [{"lang": "en", "value": "Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally."}, {"lang": "es", "value": "Lectura fuera de l\u00edmites en Microsoft Office Excel permite a un atacante no autorizado divulgar informaci\u00f3n localmente."}], "lastModified": "2026-06-17T10:18:23.123", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:*", "vulnerable": true, "matchCriteriaId": "3259EBFE-AE2D-48B8-BE9A-E22BBDB31378"}, {"criteria": "cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*", "vulnerable": true, "matchCriteriaId": "CD25F492-9272-4836-832C-8439EBE64CCF"}, {"criteria": "cpe:2.3:a:microsoft:excel:2016:*:*:*:*:*:x64:*", "vulnerable": true, "matchCriteriaId": "CD88F667-6773-4DB7-B6C3-9C7B769C0808"}, {"criteria": 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