Microsoft Security Update Guide · Office / Microsoft 365 Apps
Microsoft Office OneNote Remote Code Execution Vulnerability
Published
What does this mean?
- Remote Code Execution. An attacker can run their own code on the system remotely. This is the most serious type: it can lead to taking over the system.
- It can be exploited over the network (including from the internet if the service is reachable there), without an account and if a user takes part, for example by opening a link or file.
- CVSS 8.8 out of 10: high. Microsoft rates it Important.
- No attacks reported; Microsoft expects exploitation to be less likely.
- What should you do? Install the security update for the version you run (or a later cumulative update):
- Microsoft 365 Apps for Enterprise for 64-bit Systems: KBRelease Notes
https://aka.ms/OfficeSecurityReleases - Microsoft 365 Apps for Enterprise for 32-bit Systems: KBRelease Notes
https://aka.ms/OfficeSecurityReleases
- Microsoft 365 Apps for Enterprise for 64-bit Systems: KBRelease Notes
Improper neutralization of special elements used in a command ('command injection') in Microsoft Office OneNote allows an unauthorized attacker to execute code over a network.
What kind of flaw is this?
- CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')
Input ends up unfiltered in a command, so an attacker can run their own commands (command injection).
Key facts
Released
13 okt 2026
Impact
Remote Code Execution
Max severity
Important
Weakness
CVSS 3.1
8.8 / 7.7 (base / temporal)
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:CPublicly disclosed
No
Exploited
No
Exploitability assessment
Exploitation Less Likely
Customer action required
Yes
Links
CVSS metrics
| Base score metrics | |
|---|---|
| Attack Vector | Network |
| Attack Complexity | Low |
| Privileges Required | None |
| User Interaction | Required |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity | High |
| Availability | High |
| Temporal score metrics | |
| Exploit Code Maturity | Unproven |
| Remediation Level | Official Fix |
| Report Confidence | Confirmed |
Affected products and updates
| Product | Update | Build |
|---|---|---|
| Microsoft 365 Apps for Enterprise for 64-bit Systems | KBRelease Notes | https://aka.ms/OfficeSecurityReleases |
| Microsoft 365 Apps for Enterprise for 32-bit Systems | KBRelease Notes | https://aka.ms/OfficeSecurityReleases |
FAQ
- How could an attacker exploit this vulnerability?
- An unauthenticated attacker could send a specially crafted OneNote link and convince a user to open it. The link could cause OneNote to launch an attacker-controlled external target, which could lead to remote code execution; user interaction is required.
Revisions
| Version | Date | Note |
|---|---|---|
| 1 | 13 okt 2026 | Information published. |
This is in the weekly digest for week 42: everything that changed in Microsoft 365 this week. →
View at Microsoft → ← All security advisories
Source: Microsoft Security Update Guide. 365Fanatic is not affiliated with Microsoft.
