Out-of-bounds Read in Microsoft 365 Apps
CVE-2026-20946
Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.007 (50.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 50.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: -0.000
Affected products
- Microsoft 365 Apps
- Microsoft Excel — versions 2016
- Microsoft 365 Apps For Enterprise — versions 16.0.1
- Microsoft Excel 2016 — versions 16.0.0.0
- Microsoft Office 2019 — versions 19.0.0
- 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
- Microsoft Office — versions 2019
Weakness classification (CWE)
References
- Microsoft Excel Remote Code Execution Vulnerability (vendor-advisory, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-20946?
- CVE-2026-20946 is a high-severity vulnerability in Microsoft 365 Apps, classified under Out-of-bounds Read. CVSS score: 7.8/10. Published 2026-01-13.
- How severe is CVE-2026-20946?
- High severity. CVSS v3 base score is 7.8 out of 10.