Double free in Microsoft Office for macOS and Microsoft Office - CVE-2026-109503
Published: November 10, 2026
Vulnerability identifier: #VU164754
CSH Severity: High
CVSS v4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-109503
CWE-ID: CWE-415
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code with the victim's permissions.
The vulnerability exists due to a double free in Microsoft Office Word when processing a document for PDF export. A remote attacker can provide a specially crafted Word document and convince a user to open it and export it to PDF to execute arbitrary code with that user's permissions.
The Preview Pane is not an attack vector.
Affected software
Microsoft Office for macOS
Microsoft Office
Microsoft Office
How to mitigate CVE-2026-109503
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