Out-of-bounds read in Microsoft Word - CVE-2026-63521
Published: August 12, 2026
Vulnerability identifier: #VU141801
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-2026-63521
CWE-ID: CWE-125
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 out-of-bounds read in Microsoft Office Word when parsing a crafted document. A remote attacker can trick the victim into opening a specially crafted file to disclose sensitive information.
The disclosed information may include portions of process memory. The Preview Pane is not an attack vector for this vulnerability.
Affected software
Microsoft Word
How to mitigate CVE-2026-63521
Install security update from vendor's website.
Microsoft Word - update to 16.0.5565.1000