CVE-2026-55898

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

CVSS v3 6.1 MEDIUM

6.1^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 4.2

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact LOW

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55898	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:microsoft_365:-:::::macos::
	cpe:2.3:a:microsoft:office_2019:-::::::x64:
	cpe:2.3:a:microsoft:office_2019:-::::::x86:
	cpe:2.3:a:microsoft:office_2021:-::::ltsc:-:x64:
	cpe:2.3:a:microsoft:office_2021:-::::ltsc:-:x86:
	cpe:2.3:a:microsoft:office_2021:-::::ltsc:macos:-:
	cpe:2.3:a:microsoft:office_2024:-::::ltsc:-:x64:
	cpe:2.3:a:microsoft:office_2024:-::::ltsc:-:x86:
	cpe:2.3:a:microsoft:office_2024:-::::ltsc:macos:-:
	cpe:2.3:a:microsoft:office_online_server::::::::

History

No history.

Information

Published : 2026-07-14 18:18

Updated : 2026-07-15 17:12

NVD link : CVE-2026-55898

Mitre link : CVE-2026-55898

CVE.ORG link : CVE-2026-55898

JSON object : View

Products Affected

microsoft

office_2024
office_2019
microsoft_365
excel
365_apps
office_2021
office_online_server

CWE

CWE-125

Out-of-bounds Read

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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.2, "exploitabilityScore": 1.8}]}, "affected": [{"source": "secure@microsoft.com", "affectedData": [{"vendor": "Microsoft", "product": "Microsoft 365 Apps for Enterprise", "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 Excel 2016", "versions": [{"status": "affected", "version": "16.0.0.0", "lessThan": "16.0.5561.1001", "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 365 for Mac", "versions": [{"status": "affected", "version": "1.0.0", "lessThan": "16.111.26071215", "versionType": "custom"}]}, {"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": "16.111.26071215", "versionType": "custom"}]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC for Mac 2024", "versions": [{"status": "affected", "version": "16.0.0", "lessThan": "16.111.26071215", "versionType": "custom"}]}, {"vendor": "Microsoft", "product": "Office Online Server", "versions": [{"status": "affected", "version": "16.0.0.0", "lessThan": "16.0.10417.20175", "versionType": "custom"}]}]}], "published": "2026-07-14T18:18:21.640", "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55898", "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."}], "lastModified": "2026-07-15T17:12:17.667", "configurations": [{"nodes": [{"negate": false, "cpeMatch": 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