Vulnerability · Published Jul 14, 2026 · Assigned by microsoft
CVE-2026-55133Microsoft OneNote Remote Code Execution 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 0.5% (higher than 41% of all known vulnerabilities).
Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.5%top 59.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Heap-based buffer overflow in Microsoft Office OneNote allows an unauthorized attacker to execute code locally.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft 365 Apps for Enterprise | 16.0.1 – before https://aka.ms/OfficeSecurityReleases |
| Microsoft | Microsoft Office 365 for Mac | 1.0.0 – before 16.111.26071215 |
| Microsoft | Microsoft Office LTSC for Mac 2021 | 16.0.1 – before 16.111.26071215 |
| Microsoft | Microsoft Office LTSC for Mac 2024 | 16.0.0 – before 16.111.26071215 |
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 OneNote Remote Code Execution Vulnerability vendor-advisory, patch