Out-of-bounds read in Office Online Server and Microsoft Office - CVE-2026-97779
Published: October 14, 2026
Vulnerability identifier: #VU155601
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-97779
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose portions of process memory.
The vulnerability exists due to an out-of-bounds read in Microsoft Office Excel when processing a malicious Office file. A remote attacker can send a malicious Office file to a user and convince them to open it to disclose portions of process memory.
The Preview Pane is not an attack vector.
Affected software
Office Online Server
Microsoft Office
Microsoft Office
How to mitigate CVE-2026-97779
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
Microsoft Office - addressed in versions 16.0.14334.20974, 16.0.17932.21056