Off-by-one in Microsoft Word - CVE-2026-66806
Published: August 12, 2026
Vulnerability identifier: #VU141985
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-2026-66806
CWE-ID: CWE-193
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to off-by-one error in Microsoft Office Word when parsing a specially crafted file. A remote attacker can trick the victim into opening a crafted file to disclose sensitive information.
The disclosed information may include portions of process memory. The Preview Pane is not an attack vector.
Affected software
Microsoft Word
How to mitigate CVE-2026-66806
Install security update from vendor's website.
Microsoft Word - update to 16.0.5565.1000