Medium severity · published Aug 11, 2026
CVE-2026-63521
Microsoft Office Word Information Disclosure Vulnerability
5.5
CVSS
0.4%
EPSS
No
On KEV
Description
Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information locally.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OF
Office · Microsoft
All versions, or not specified · source: NVD
M3
Microsoft 365 Apps for Enterprise · Microsoft
16.0.1 before https://aka.ms/OfficeSecurityReleases · source: vendor
MO
Microsoft Office 2019 · Microsoft
19.0.0 before https://aka.ms/OfficeSecurityReleases · source: vendor
MO
Microsoft Office LTSC 2021 · Microsoft
16.0.1 before https://aka.ms/OfficeSecurityReleases · source: vendor
MO
Microsoft Office LTSC 2024 · Microsoft
16.0.0 before https://aka.ms/OfficeSecurityReleases · source: vendor
MW
Microsoft Word 2016 · Microsoft
16.0.1 before 16.0.5565.1000 · source: vendor
O2
Office 2019 · Microsoft
All versions, or not specified · source: NVD
O2
Office 2021 · Microsoft
All versions, or not specified · source: NVD
O2
Office 2024 · Microsoft
All versions, or not specified · source: NVD
WO
Word · Microsoft
2016; 2016 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-63521
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-63521
vendor-advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-63521
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