Microsoft Security Update Guide · Office / Microsoft 365 Apps
Microsoft Office Click-To-Run Elevation of Privilege Vulnerability
Published
What does this mean?
- Elevation of Privilege. An attacker can gain more rights than they should have, for example admin rights.
- It can be exploited with access to the device itself, with an ordinary user account and without any user action.
- CVSS 7.0 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: KBClick to Run
https://aka.ms/OfficeSecurityReleases - Microsoft 365 Apps for Enterprise for 32-bit Systems: KBClick to Run
https://aka.ms/OfficeSecurityReleases
- Microsoft 365 Apps for Enterprise for 64-bit Systems: KBClick to Run
Time-of-check time-of-use (toctou) race condition in Microsoft Office Click-To-Run allows an authorized attacker to elevate privileges locally.
Key facts
Released
13 okt 2026
Impact
Elevation of Privilege
Max severity
Important
Weakness
CVSS 3.1
7.0 / 6.1 (base / temporal)
Vector string
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/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 | Local |
| Attack Complexity | High |
| Privileges Required | Low |
| User Interaction | None |
| 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 | KBClick to Run | https://aka.ms/OfficeSecurityReleases |
| Microsoft 365 Apps for Enterprise for 32-bit Systems | KBClick to Run | https://aka.ms/OfficeSecurityReleases |
FAQ
- According to the CVSS metric, the attack vector is local (AV:L). How could an attacker exploit this elevation of privilege vulnerability?
- An attacker could exploit this elevation of privilege vulnerability by first establishing a foothold on the local system such as opening a malicious document or gaining access through another local vector and then leveraging the flaw to break out of the Protected View sandbox. Protected View is intended to isolate untrusted content in a restricted environment; however, successful exploitation would allow the attacker to escape these restrictions and execute code with elevated privileges on the host system.
- According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
- Successful exploitation of this vulnerability requires an attacker to win a race condition.
- What privileges could be gained by an attacker who successfully exploited this vulnerability?
- An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.
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.
