Vulnerability · Published Feb 10, 2026 · Assigned by microsoft
CVE-2026-21259Microsoft Excel Elevation of Privilege Vulnerability
High 7.8
In plain English
A high-severity heap buffer overflow in Microsoft 365 Apps for Enterprise from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 46% of all known vulnerabilities).
Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.6%top 53.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to elevate privileges locally.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft 365 Apps for Enterprise | 16.0.1 – before https://aka.ms/OfficeSecurityReleases |
| Microsoft | Microsoft Excel 2016 | 16.0.0.0 – before 16.0.5539.1002 |
| Microsoft | Microsoft Office 2019 | 19.0.0 – before https://aka.ms/OfficeSecurityReleases |
| Microsoft | Microsoft Office LTSC 2021 | 16.0.1 – before https://aka.ms/OfficeSecurityReleases |
| Microsoft | Microsoft Office LTSC 2024 | 16.0.0 – before https://aka.ms/OfficeSecurityReleases |
| Microsoft | Office Online Server | 16.0.0.0 – before 16.0.10417.20097 |
Weakness: CWE-122 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
References
- Microsoft Excel Elevation of Privilege Vulnerability vendor-advisory, patch