Heap-based buffer overflow in Office Online Server and Microsoft Office - CVE-2026-100210
Published: October 13, 2026
Vulnerability identifier: #VU154234
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-2026-100210
CWE-ID: CWE-122
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 a heap-based buffer overflow 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 execute arbitrary code.
The Preview Pane is not an attack vector.
Affected software
Office Online Server
Microsoft Office
Microsoft Office
How to mitigate CVE-2026-100210
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