Integer overflow in Microsoft 365 Apps
CVE-2026-70329
Integer overflow or wraparound in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.
Vulnerability class: Integer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.008 (55.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 55.5% 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: 0.008 · change: +0.001
Affected products
- Microsoft 365 Apps
- Microsoft 365 Apps For Enterprise — versions 16.0.1
- Microsoft Office 2019 — versions 19.0.0
- Microsoft Office Ltsc 2021 — versions 16.0.1
- Microsoft Office Ltsc 2024 — versions 16.0.0
- Microsoft Outlook 2016 — versions 16.0.0.0
- Microsoft Office 2019
- Microsoft Office 2021
- Microsoft Office 2024
- Microsoft Outlook — versions 2016
Weakness classification (CWE)
References
- Microsoft Outlook Remote Code Execution Vulnerability (vendor-advisory, Patch, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-70329?
- CVE-2026-70329 is a high-severity vulnerability in Microsoft 365 Apps, classified under Integer Overflow or Wraparound. CVSS score: 8.8/10. Published 2026-08-11.
- How severe is CVE-2026-70329?
- High severity. CVSS v3 base score is 8.8 out of 10.