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MEDIUM · 5.5

CVE-2026-55138

Untrusted pointer dereference in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

Vulnerability Description

Untrusted pointer dereference in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

CVSS Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE

Affected Products

VendorProductVersions
Microsoft365 Apps-
MicrosoftExcel2016
MicrosoftMicrosoft 365-
MicrosoftOffice 2019-
MicrosoftOffice 2021-
MicrosoftOffice 2024-
MicrosoftOffice Online Server< 16.0.10417.20175

Related Weaknesses (CWE)

CWE-822

References

FAQ

What is CVE-2026-55138?

CVE-2026-55138 is a vulnerability with a CVSS score of 5.5 (MEDIUM). Untrusted pointer dereference in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

How severe is CVE-2026-55138?

CVE-2026-55138 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-55138?

Check the references section above for vendor advisories and patch information. Affected products include: Microsoft 365 Apps, Microsoft Excel, Microsoft Microsoft 365, Microsoft Office 2019, Microsoft Office 2021.