CVE-2026-123378

Microsoft Office Outlook Remote Code Execution Vulnerability

Published Nov 10, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
Integer overflow or wraparound in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
Description Integer overflow or wraparound in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.
Title Microsoft Office Outlook Remote Code Execution Vulnerability
First Time appeared Microsoft
Microsoft 365 Apps
Microsoft office 2021
Microsoft office 2024
Weaknesses CWE-122
CWE-190
CPEs cpe:2.3:a:microsoft:365_apps:*:*:*:*:enterprise:*:*:*
cpe:2.3:a:microsoft:office_2021:*:*:*:*:long_term_servicing_channel:*:*:*
cpe:2.3:a:microsoft:office_2024:*:*:*:*:long_term_servicing_channel:*:*:*
Vendors & Products Microsoft
Microsoft 365 Apps
Microsoft office 2021
Microsoft office 2024
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
microsoft
Published
Updated
Nov 13, 2026, 6:10 PM
Reserved
Nov 5, 2026, 9:53 PM
Status
Awaiting Analysis
Published
Nov 10, 2026, 7:20 PM
Modified
Nov 10, 2026, 9:19 PM