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Description

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

PUBLISHED Reserved 2025-12-11 | Published 2026-02-10 | Updated 2026-02-23 | Assigner microsoft




MEDIUM: 5.5CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C

Problem types

CWE-20: Improper Input Validation

CWE-125: Out-of-bounds Read

Product status

16.0.1 (custom) before https://aka.ms/OfficeSecurityReleases
affected

16.0.0.0 (custom) before 16.0.5539.1002
affected

19.0.0 (custom) before https://aka.ms/OfficeSecurityReleases
affected

16.0.1 (custom) before https://aka.ms/OfficeSecurityReleases
affected

16.0.0 (custom) before https://aka.ms/OfficeSecurityReleases
affected

16.0.1 (custom) before 16.106.26020821
affected

16.0.0 (custom) before 16.106.26020821
affected

16.0.0.0 (custom) before 16.0.10417.20097
affected

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21258 (Microsoft Excel Information Disclosure Vulnerability) vendor-advisory patch

cve.org (CVE-2026-21258)

nvd.nist.gov (CVE-2026-21258)

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