Deserialization of Untrusted Data in Microsoft Office for macOS and Microsoft Office - CVE-2026-124229
Published: November 11, 2026
Vulnerability identifier: #VU165503
CSH Severity: Medium
CVSS v4: 7 [CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-124229
CWE-ID: CWE-502
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an attacker with physical access to system to execute arbitrary code.
The vulnerability exists due to deserialization of untrusted data in Microsoft Office Excel when processing serialized input. An attacker with physical access to system can exploit the processing of crafted serialized data through physical access, with user interaction, to execute arbitrary code.
The Preview Pane is not an attack vector for this vulnerability.
Affected software
Microsoft Office for macOS
Microsoft Office
Microsoft Office
How to mitigate CVE-2026-124229
Install security update from vendor's website.
Microsoft Office for macOS - update to 16.115.26110837
Microsoft Office - addressed in versions 16.0.14334.21048, 16.0.17932.21140
Microsoft Office - addressed in versions 16.0.14334.21048, 16.0.17932.21140