Microsoft Security Update Guide · Office / Microsoft 365 Apps
Microsoft Office Outlook Information Disclosure Vulnerability
Published
What does this mean?
- Information Disclosure. An attacker can see information that is not meant for them.
- It can be exploited over the network (including from the internet if the service is reachable there), without an account and without any user action.
- CVSS 7.5 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 Office LTSC for Mac 2024: KBRelease Notes
- Microsoft Office LTSC 2024 for 32-bit editions: KBRelease Notes
16.0.17932.21056 - Microsoft Office LTSC 2024 for 64-bit editions: KBRelease Notes
16.0.17932.21056 - Microsoft Office LTSC 2021 for 64-bit editions: KBRelease Notes
16.0.14334.20974 - Microsoft 365 Apps for Enterprise for 64-bit Systems: KBRelease Notes
https://aka.ms/OfficeSecurityReleases - Microsoft Office LTSC 2021 for 32-bit editions: KBRelease Notes
16.0.14334.20974
Out-of-bounds read in Microsoft Office Outlook allows an unauthorized attacker to disclose information over a network.
Outlook Office / Microsoft 365 Apps
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.
What kind of flaw is this?
- CWE-125: Out-of-bounds Read
The program reads outside its allocated memory and can leak information.
Key facts
Released
13 okt 2026
Impact
Information Disclosure
Max severity
Important
Weakness
CVSS 3.1
7.5 / 6.5 (base / temporal)
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/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 | None |
| 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 | — |
| Microsoft Office LTSC 2024 for 32-bit editions | KBRelease Notes | 16.0.17932.21056 |
| Microsoft Office LTSC 2024 for 64-bit editions | KBRelease Notes | 16.0.17932.21056 |
| Microsoft Office LTSC 2021 for 64-bit editions | KBRelease Notes | 16.0.14334.20974 |
| Microsoft 365 Apps for Enterprise for 64-bit Systems | KBRelease Notes | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office LTSC 2021 for 32-bit editions | KBRelease Notes | 16.0.14334.20974 |
| Microsoft Office LTSC for Mac 2021 | KBRelease Notes | — |
| Microsoft 365 Apps for Enterprise for 32-bit Systems | KBRelease Notes | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office 365 for Mac | KBRelease Notes | — |
FAQ
- Are the updates for the Microsoft Office LTSC for Mac currently available?
- The security update for Microsoft Office LTSC for Mac 2021 and 2024 are not immediately available. The updates will be released as soon as possible, and when they are available, customers will be notified via a revision to this CVE information.
- 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.
- Is the Preview Pane an attack vector for this vulnerability?
- Yes, the Preview Pane is an attack vector.
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.
