Microsoft Security Update Guide · Office / Microsoft 365 Apps
Microsoft Office Remote Code Execution Vulnerability
Published · updated 19 jun 2026
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 with access to the device itself, without an account and without any user action.
- CVSS 8.4 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 2016 (64-bit edition): KB5002878
16.0.5556.1005 - Microsoft Office 2016 (32-bit edition): KB5002878
16.0.5556.1005 - Microsoft Office LTSC for Mac 2024: KBRelease Notes
16.110.26061317 - Microsoft Office LTSC 2024 for 64-bit editions: KBClick to Run
https://aka.ms/OfficeSecurityReleases - Microsoft Office LTSC 2024 for 32-bit editions: KBClick to Run
https://aka.ms/OfficeSecurityReleases - Microsoft Office LTSC 2021 for 32-bit editions: KBClick to Run
https://aka.ms/OfficeSecurityReleases
- Microsoft Office 2016 (64-bit edition): KB5002878
Integer underflow (wrap or wraparound) in Microsoft Office allows an unauthorized attacker to execute code locally.
How do I check if I am affected?
Update the app
- Update the app through the App Store, Google Play or the app's own automatic updates.
- If you manage devices with Intune, check in the Intune admin center which devices still run an older version.
Key facts
Released
9 jun 2026
Last revised
19 jun 2026 (v3)
Impact
Remote Code Execution
Max severity
Critical
Weakness
CVSS 3.1
8.4 / 7.3 (base / temporal)
Vector string
CVSS:3.1/AV:L/AC:L/PR:N/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 | Low |
| Privileges Required | None |
| 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 Office 2016 (64-bit edition) | KB5002878 · Security Update | 16.0.5556.1005 |
| Microsoft Office 2016 (32-bit edition) | KB5002878 · Security Update | 16.0.5556.1005 |
| Microsoft Office LTSC for Mac 2024 | KBRelease Notes · Security Update | 16.110.26061317 |
| Microsoft Office LTSC 2024 for 64-bit editions | KBClick to Run | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office LTSC 2024 for 32-bit editions | KBClick to Run | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office LTSC 2021 for 32-bit editions | KBClick to Run | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office LTSC 2021 for 64-bit editions | KBClick to Run | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office LTSC for Mac 2021 | KBRelease Notes · Security Update | 16.110.26061317 |
| 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 Office 2019 for 64-bit editions | KBClick to Run | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office 2019 for 32-bit editions | KBClick to Run | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office for Android | KBRelease Notes · Security Update | 16.0.20131.20024 |
| Microsoft Office 365 for Mac | KBRelease Notes · Security Update | 16.110.26061317 |
FAQ
- According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution?
- The word Remote in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally. This means an attacker or victim needs to execute code from the local machine to exploit the vulnerability.
- Is the Preview Pane an attack vector for this vulnerability?
- Yes, the Preview Pane is an attack vector.
- Are the updates for Microsoft Office LTSC for Mac 2021 and 2024 currently available?
- Yes. As of June 16, 2025, the security update for Microsoft Office LTSC for Mac 2021, 2024 and Microsoft Office 365 for Mac are available. Customers running Microsoft Office LTSC for Mac 2021, 2024 and Microsoft Office 365 for Mac should ensure the update is installed to be protected from this vulnerability.
- Are the updates for Microsoft Office for Android currently available?
- Yes. As of June 15, 2026, the security update for Microsoft Office for Android are available. Customers running Microsoft Office for Android should ensure the update is installed to be protected from this vulnerability.
Revisions
| Version | Date | Note |
|---|---|---|
| 2 | 19 jun 2026 | Microsoft is announcing the availability of the security updates for Microsoft Office for Mac. Customers running affected Mac software should install the update for their product to be protected from this vulnerability. Customers running other Microsoft Office software do not need to take any action. See the Release Notes for more information and download links. |
| 3 | 19 jun 2026 | Microsoft is announcing the availability of the security updates for Microsoft Office for Android. Customers running affected Microsoft Office for Android software should install the update for their product to be protected from this vulnerability. |
| 1 | 9 jun 2026 | Information published. |
What changed in Microsoft 365 this week? →
View at Microsoft → ← All security advisories
Source: Microsoft Security Update Guide. 365Fanatic is not affiliated with Microsoft.
