Buffer overflow in Microsoft 365 Apps
CVE-2026-45463
Integer underflow (wrap or wraparound) in Microsoft Office allows an unauthorized attacker to execute code locally.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.4 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (27.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 27.8% 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: 0.004 · change: 0.000
Affected products
- Microsoft 365 Apps
- Microsoft 365 Copilot
- 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 For Android — versions 16.0.1
- Microsoft Office Ltsc 2021 — versions 16.0.1
- Microsoft Office Ltsc 2024 — versions 16.0.0
Weakness classification (CWE)
References
- Microsoft Office Remote Code Execution Vulnerability (vendor-advisory, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-45463?
- CVE-2026-45463 is a high-severity vulnerability in Microsoft 365 Apps, classified under Stack-based Buffer Overflow. CVSS score: 8.4/10. Published 2026-06-09.
- How severe is CVE-2026-45463?
- High severity. CVSS v3 base score is 8.4 out of 10.