Use-after-free in Microsoft products - CVE-2026-78525
Published: September 9, 2026
Vulnerability identifier: #VU148243
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-2026-78525
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to use-after-free in Microsoft Office Outlook when processing a specially crafted email. A remote attacker can send a specially crafted email to execute arbitrary code.
The victim must open the specially crafted email or Outlook must display a preview of it.
Affected software
Microsoft Word
Microsoft 365 Apps for Enterprise
Microsoft Office
Microsoft 365 Apps for Enterprise
Microsoft Office
How to mitigate CVE-2026-78525
Install security update from vendor's website.
Microsoft Word - update to 16.0.5569.1000
Microsoft 365 Apps for Enterprise - update to 16.0.20326.20138
Microsoft Office - addressed in versions 16.0.10417.20207, 16.0.14334.20906, 16.0.17932.20976
Microsoft 365 Apps for Enterprise - update to 16.0.20326.20138
Microsoft Office - addressed in versions 16.0.10417.20207, 16.0.14334.20906, 16.0.17932.20976