CVE-2026-55046

Microsoft Excel Information Disclosure Vulnerability

Published Jul 14, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

Analysis

AI-generated

Technical impact

This vulnerability is an out-of-bounds read flaw that lets a local attacker read data that the application should not expose. The weakness is classified as CWE-125, are insufficient. No evidence of remote code execution or denial of service is provided, so the impact is confined to local knowledge gain of sensitive information stored inside or adjacent to Excel memory.

Affected Systems

Affected products include Microsoft 365 Apps for Enterprise, Microsoft Excel 2016, Microsoft Office 2019, Microsoft Office 365 for Mac, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, Microsoft Office LTSC for Mac 2021, Microsoft Office LTSC for Mac 2024, and Office Online Server. No specific vulnerable version numbers are listed in the CNA data, so all current releases of these products are potentially impacted.

Risk and Exploitability

The CVSS score of 5.5 indicates a medium severity and the EPSS score of less than 1% indicates a very low probability of exploitation in the wild. The vulnerability does not appear in CISA’s KEV a locally executed exploit would be needed to trigger the out-of-bounds read.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Install the latest Microsoft Office security update that contains the fix for CVE-2026-55046, which can be retrieved through Microsoft Update or the Microsoft Security Response Center update guide.
  • Apply the principle of least privilege to users who run Office applications by limiting their file system permissions and restricting access to documents that may contain sensitive data.
  • Disable or sandbox any automated processes that trigger could exploit the read flaw.

Generated by OpenCVE AI on July 31, 2026 at 07:05 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Microsoft office Online Server
Vendors & Products Microsoft office Online Server
Type Values Removed Values Added
Description Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.
Title Microsoft Excel Information Disclosure Vulnerability
First Time appeared Microsoft
Microsoft 365 Apps
Microsoft excel 2016
Microsoft office 2019
Microsoft office 2021
Microsoft office 2024
Microsoft office 365
Microsoft office Macos 2021
Microsoft office Macos 2024
Weaknesses CWE-125
CPEs cpe:2.3:a:microsoft:365_apps:*:*:*:*:enterprise:*:*:*
cpe:2.3:a:microsoft:excel_2016:*:*:*:*:*:*:x86:*
cpe:2.3:a:microsoft:office_2019:*:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:office_2021:*:*:*:*:long_term_servicing_channel:*:*:*
cpe:2.3:a:microsoft:office_2021:*:*:*:*:ltsc:*:*:*
cpe:2.3:a:microsoft:office_2024:*:*:*:*:long_term_servicing_channel:*:*:*
cpe:2.3:a:microsoft:office_365:*:*:*:*:*:macos:*:*
cpe:2.3:a:microsoft:office_macos_2021:*:*:*:*:*:long_term_servicing_channel:*:*
cpe:2.3:a:microsoft:office_macos_2024:*:*:*:*:*:long_term_servicing_channel:*:*
Vendors & Products Microsoft
Microsoft 365 Apps
Microsoft excel 2016
Microsoft office 2019
Microsoft office 2021
Microsoft office 2024
Microsoft office 365
Microsoft office Macos 2021
Microsoft office Macos 2024
References
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C'}