Out-of-bounds Read in Microsoft 365 Apps
CVE-2026-63517
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.005 (43.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.002
Affected products
- Microsoft 365 Apps
- Microsoft 365
- Microsoft 365 Apps For Enterprise — versions 16.0.1
- Microsoft Office 2016 — versions 16.0.0
- Microsoft Office 2019 — versions 19.0.0
- Microsoft Office 365 For Mac — versions 1.0.0
- Microsoft Office Ltsc 2021 — versions 16.0.1
- Microsoft Office Ltsc 2024 — versions 16.0.0
- Microsoft Office Ltsc For Mac 2021 — versions 16.0.1
- Microsoft Office Ltsc For Mac 2024 — versions 16.0.0
Weakness classification (CWE)
References
- Microsoft Office Graphics Component Information Disclosure Vulnerability (vendor-advisory, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-63517?
- CVE-2026-63517 is a medium-severity vulnerability in Microsoft 365 Apps, classified under Out-of-bounds Read. CVSS score: 5.5/10. Published 2026-08-11.
- How severe is CVE-2026-63517?
- Medium severity. CVSS v3 base score is 5.5 out of 10.