Microsoft Security Update Guide · Office / Microsoft 365 Apps
Microsoft Office Outlook 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 Critical.
- 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 Office LTSC 2024 for 32-bit editions: KBRelease Notes
16.0.17932.20976 - Microsoft Office LTSC 2021 for 64-bit editions: KBRelease Notes
16.0.14334.20906 - Microsoft Office LTSC 2021 for 32-bit editions: KBRelease Notes
16.0.14334.20906 - Microsoft Office LTSC 2024 for 64-bit editions: KBRelease Notes
16.0.17932.20976 - Microsoft Outlook 2016 (64-bit edition): KB5002919
16.0.5569.1000 - Microsoft Outlook 2016 (32-bit edition): KB5002919
16.0.5569.1000
- Microsoft Office LTSC 2024 for 32-bit editions: KBRelease Notes
Use of uninitialized resource in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.
Outlook Office / Microsoft 365 Apps
Key facts
Released
8 sep 2026
Impact
Remote Code Execution
Max severity
Critical
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 Office LTSC 2024 for 32-bit editions | KBRelease Notes | 16.0.17932.20976 |
| Microsoft Office LTSC 2021 for 64-bit editions | KBRelease Notes | 16.0.14334.20906 |
| Microsoft Office LTSC 2021 for 32-bit editions | KBRelease Notes | 16.0.14334.20906 |
| Microsoft Office LTSC 2024 for 64-bit editions | KBRelease Notes | 16.0.17932.20976 |
| Microsoft Outlook 2016 (64-bit edition) | KB5002919 · Security Update | 16.0.5569.1000 |
| Microsoft Outlook 2016 (32-bit edition) | KB5002919 · Security Update | 16.0.5569.1000 |
| Microsoft 365 Apps for Enterprise for 64-bit Systems | KBRelease Notes | 16.0.20326.20138 |
| Microsoft 365 Apps for Enterprise for 32-bit Systems | KBRelease Notes | 16.0.20326.20138 |
| Microsoft Office 2019 for 64-bit editions | KBRelease Notes | 16.0.10417.20207 |
| Microsoft Office 2019 for 32-bit editions | KBRelease Notes | 16.0.10417.20207 |
FAQ
- How could an attacker exploit the vulnerability?
- In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted email to the victim. Exploitation of the vulnerability might involve either a victim opening a specially crafted email with an affected version of Microsoft Outlook software, or a victim's Outlook application displaying a preview of a specially crafted email . This could result in the attacker executing remote code on the victim's machine.
- Is the Preview Pane an attack vector for this vulnerability?
- Yes, the Preview Pane is an attack vector.
Revisions
| Version | Date | Note |
|---|---|---|
| 1 | 8 sep 2026 | Information published. |
This is in the weekly digest for week 37 · What changed this week? →
View at Microsoft → ← All security advisories
Source: Microsoft Security Update Guide. 365Fanatic is not affiliated with Microsoft.
