Local information disclosure via out-of-bounds read
Published Aug 11, 2026 · Updated Aug 29, 2026
Out-of-bounds read in Microsoft Office Word allows local users to disclose sensitive information after user interaction. Microsoft has not published the affected Word parser, input structure, or the read operation that crosses a buffer boundary. Exploitation requires local execution and user interaction; the documented consequence is information disclosure without integrity or availability impact.
Summary
What happened
Out-of-bounds read in Microsoft Office Word allows local users to disclose sensitive information after user interaction. Microsoft has not published the affected Word parser, input structure, or the read operation that crosses a buffer boundary. Exploitation requires local execution and user interaction; the documented consequence is information disclosure without integrity or availability impact.
The record
- CVE
- CVE-2026-63521
- Published
- Aug 11, 2026
- Updated
- Aug 29, 2026
- Vendor
- Microsoft
- Product
- Microsoft Office 2019
- Classifications
- CWE-125
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 11, 2026CVE publishedPublication date reported by the CVE source.
- Aug 29, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=19.0.0 <https://aka.ms/OfficeSecurityReleases
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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