Use-after-free in Office Online Server and Microsoft Office - CVE-2026-97771

 

Use-after-free in Office Online Server and Microsoft Office - CVE-2026-97771

Published: October 14, 2026


Vulnerability identifier: #VU155593
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-2026-97771
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 Excel when processing a specially crafted file. A remote attacker can trick a user into opening the file to execute arbitrary code.

The Preview Pane is not an attack vector.


Affected software

Office Online Server
Microsoft Office

How to mitigate CVE-2026-97771

Install security update from vendor's website.

Office Online Server - update to 16.0.10417.20228
Microsoft Office - addressed in versions 16.0.14334.20974, 16.0.17932.21056

External References

Related Security Bulletins