Microsoft Security Update Guide · Office / Microsoft 365 Apps
Microsoft Word 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 if a user takes part, for example by opening a link or file.
- CVSS 6.5 out of 10: medium. 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 365 for Mac: KBRelease Notes
16.112.26081010 - Microsoft Word 2016 (64-bit edition): KB5002901
16.0.5565.1000 - Microsoft Word 2016 (32-bit edition): KB5002901
16.0.5565.1000 - Microsoft Office LTSC for Mac 2024: KBRelease Notes
16.112.26081010 - 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 365 for Mac: KBRelease Notes
Improper input validation in Microsoft Office Word allows an unauthorized attacker to disclose information over a network.
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-20: Improper Input Validation
Input is not checked well enough before the software uses it.
Key facts
Released
20 aug 2026
Impact
Information Disclosure
Max severity
Important
Weakness
CVSS 3.1
6.5 / 5.7 (base / temporal)
Vector string
CVSS:3.1/AV:N/AC:L/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 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 | 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 365 for Mac | KBRelease Notes · Security Update | 16.112.26081010 |
| Microsoft Word 2016 (64-bit edition) | KB5002901 · Security Update | 16.0.5565.1000 |
| Microsoft Word 2016 (32-bit edition) | KB5002901 · Security Update | 16.0.5565.1000 |
| Microsoft Office LTSC for Mac 2024 | KBRelease Notes · Security Update | 16.112.26081010 |
| 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 | 16.112.26081010 |
| 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 |
FAQ
- Is the Preview Pane an attack vector for this vulnerability?
- No, the Preview Pane is not an attack vector.
- 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.
Revisions
| Version | Date | Note |
|---|---|---|
| 1.1 | 20 aug 2026 | Information published. This CVE was addressed by updates that were released in August 2026, but the CVE was inadvertently omitted from the August 2026 Security Updates. This is an informational change only. Customers who have already installed the August 2026 updates do not need to take any further action. |
| 1 | 20 aug 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.
