CVE-2026-21258

CWE-20 — Improper Input ValidationCWE-125 — Out-of-bounds Read5 documents5 sources
Severity
5.5MEDIUM
EPSS
0.1%
top 82.25%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
11
Microsoft Microsoft 365 Apps FOR EnterpriseMicrosoft Microsoft Excel 2016Microsoft Microsoft Office 2019+8 more
Timeline
PublishedFeb 10

Description

Improper input validation in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:NExploitability: 1.8 | Impact: 3.6

Affected Packages12 packages

▶CVEListV5microsoft/microsoft_excel_201616.0.0.0 — 16.0.5539.1002
▶CVEListV5microsoft/office_online_server16.0.0.0 — 16.0.10417.20097
▶NVDmicrosoft/office_online_server< 16.0.10417.20097
▶CVEListV5microsoft/microsoft_office_201919.0.0 — https://aka.ms/OfficeSecurityReleases
▶CVEListV5microsoft/microsoft_office_ltsc_202116.0.1 — https://aka.ms/OfficeSecurityReleases

🔴Vulnerability Details

2
GHSA
GHSA-v8pc-rxff-x74j: Improper input validation in Microsoft Office Excel allows an unauthorized attacker to disclose information locally↗2026-02-10
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CVEList
Microsoft Excel Information Disclosure Vulnerability↗2026-02-10
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📋Vendor Advisories

1
Microsoft
Microsoft Excel Information Disclosure Vulnerability↗2026-02-10
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🕵️Threat Intelligence

1
Wiz
CVE-2026-21258 Impact, Exploitability, and Mitigation Steps | Wiz↗
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