Heap-based buffer overflow in Microsoft Office - CVE-2026-123379
Published: November 11, 2026
Vulnerability identifier: #VU165475
CSH Severity: Medium
CVSS v4: 7.1 [CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-123379
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code on a system running Microsoft Office Outlook.
The vulnerability exists due to a heap-based buffer overflow in Microsoft Office Outlook when processing a large, specially crafted message. A remote attacker can send such a message and induce user interaction with it to trigger memory corruption and execute arbitrary code.
Successful exploitation requires the targeted system to have sufficient available memory to process the crafted message.
Affected software
Microsoft Office
How to mitigate CVE-2026-123379
Install security update from vendor's website.
Microsoft Office - addressed in versions 16.0.14334.21048, 16.0.17932.21140