CVE-2026-55139

Microsoft Office 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 allows an unauthorized attacker to disclose information locally.

Analysis

AI-generated

Technical impact

A bug in Microsoft Office permits an out‑of‑bounds read that can be triggered by reading data beyond intended memory or file boundaries, potentially exposing sensitive information stored on the system. The vulnerability is categorized as CWE‑125 and does not provide any code execution or remote reach.

Affected Systems

Affected products include Microsoft 365 Apps for Enterprise, Microsoft Office 2016, Microsoft Office 2019, Microsoft Office 365 for Mac, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, Microsoft Office LTSC for Mac 2021, and Microsoft Office LTSC for Mac 2024. All Windows and macOS installations of these products are vulnerable. Specific version information is not provided in the CNA data.

Risk and Exploitability

The CVSS score of 5.5 indicates moderate severity. An EPSS below 1 % suggests that exploitation is currently unlikely. The vulnerability is not listed in the CISA KEV catalog. Attackers must have local access to the Office installation. The impact is limited to information disclosure.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Install the latest Microsoft Office security updates released by Microsoft.
  • Disable macros, enable Protected View for files from the internet, and isolate documents in a sandbox or read‑only folder to prevent processing until the update is applied.
  • If a patch is not yet available, restrict local user access to the Office installation by applying file permissions or disabling the affected feature.
  • Subscribe to the Microsoft Security Response Center and monitor for new advisories.

Generated by OpenCVE AI on July 31, 2026 at 06:43 UTC.

Tracking

Sign in to view the affected projects.

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
Description Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
Title Microsoft Office Information Disclosure Vulnerability
First Time appeared Microsoft
Microsoft 365 Apps
Microsoft office 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:office_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_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 office 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:N/I:N/A:H/E:U/RL:O/RC:C'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
microsoft
Published
Updated
Nov 10, 2026, 10:39 PM
Reserved
Jun 16, 2026, 3:03 PM
Status
Analyzed
Published
Jul 14, 2026, 6:18 PM
Modified
Jul 16, 2026, 4:00 PM