Microsoft Security Update Guide · Office / Microsoft 365 Apps
Microsoft Office Information Disclosure Vulnerability
Published · updated 19 jun 2026
What does this mean?
- Information Disclosure. An attacker can see information that is not meant for them.
- It can be exploited with access to the device itself, without an account and if a user takes part, for example by opening a link or file.
- CVSS 4.7 out of 10: medium. 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 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 LTSC 2021 for 64-bit editions: KBClick to Run
https://aka.ms/OfficeSecurityReleases - Microsoft Office LTSC for Mac 2021: KBRelease Notes
16.110.26061317
- Microsoft Office LTSC for Mac 2024: KBRelease Notes
Buffer over-read in Microsoft Office allows an unauthorized attacker to disclose information 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
Information Disclosure
Max severity
Critical
Weakness
CVSS 3.1
4.7 / 4.1 (base / temporal)
Vector string
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:CPublicly disclosed
No
Exploited
No
Exploitability assessment
Exploitation Unlikely
Customer action required
Yes
Links
CVSS metrics
| Base score metrics | |
|---|---|
| Attack Vector | Local |
| Attack Complexity | High |
| Privileges Required | None |
| User Interaction | Required |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity | None |
| Availability | None |
| Temporal score metrics | |
| Exploit Code Maturity | Unproven |
| Remediation Level | Official Fix |
| Report Confidence | Confirmed |
Affected products and updates
| Product | Update | Build |
|---|---|---|
| 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 365 for Mac | KBRelease Notes · Security Update | 16.110.26061317 |
| Microsoft Office for Android | KBRelease Notes · Security Update | 16.0.20131.20024 |
FAQ
- What type of information could be disclosed by this vulnerability?
- An attacker who successfully exploited this vulnerability could potentially read small portions of heap memory.
- According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do?
- An attacker must send a user a malicious Office file and convince them to open it.
- 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. |
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Source: Microsoft Security Update Guide. 365Fanatic is not affiliated with Microsoft.
