Microsoft Excel Information Disclosure Vulnerability
Published September 8, 2026Updated September 17, 2026
Source data
Overview
Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.
Impact & technical details
Information Disclosure
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 portions of process memory.
Are the updates for Microsoft Office LTSC for Mac 2021 and 2024 currently available? Yes. As of September 16, 2026, 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.
- CVSS base score
- 5.5 / 10
- CVSS vector
- CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
Highest base score supplied by MSRC for this record; the vector belongs to that score. Ratings can vary by product. Microsoft Important is displayed as High; Moderate is displayed as Medium.
Affected products
- Microsoft 365 Apps for Enterprise for 32-bit Systems
- Microsoft 365 Apps for Enterprise for 64-bit Systems
- Microsoft Excel 2016 (32-bit edition)
- Microsoft Excel 2016 (64-bit edition)
- Microsoft Office 2016 (32-bit edition)
- Microsoft Office 2016 (64-bit edition)
- Microsoft Office 2019 for 32-bit editions
- Microsoft Office 2019 for 64-bit editions
Show all 15 affected products
- Microsoft Office 365 for Mac
- Microsoft Office LTSC 2021 for 32-bit editions
- Microsoft Office LTSC 2021 for 64-bit editions
- Microsoft Office LTSC 2024 for 32-bit editions
- Microsoft Office LTSC 2024 for 64-bit editions
- Microsoft Office LTSC for Mac 2021
- Microsoft Office LTSC for Mac 2024
Source guidance
Remediation
- Release Notes
At least one Microsoft vendor-fix reference is available. Check each affected product for its applicable update, prerequisites, and supported version.
GTP recommendation · Rule-based guidance
Recommended next step
Review affected Microsoft products and apply the applicable security updates through your organization's normal patch-management process. Confirm availability and prerequisites in the Microsoft advisory.
Authoritative sources & updates
Findings and update information come from the linked publishers. GTP compiles the public record and provides the recommendation above. CVSS ratings shown here come from Microsoft. NVD references provide additional public context.
- Microsoft Security Response Center (opens in a new tab)
- Microsoft remediation guidance (opens in a new tab)
- Microsoft remediation guidance (opens in a new tab)
- Microsoft security update · Release Notes (opens in a new tab)
- Microsoft security update · 5002914 (opens in a new tab)
- Microsoft remediation guidance (opens in a new tab)
- Microsoft security update · 5002904 (opens in a new tab)
- Microsoft remediation guidance (opens in a new tab)
- Microsoft security update · Release Notes (opens in a new tab)
Managed by GTP?
Griffin Technology Partners managed customers may receive additional environment-specific security guidance and remediation assistance through their managed services relationship.
Security bulletins are provided for informational purposes and compiled from authoritative public sources. Vulnerability applicability varies by environment. Validate affected products, configuration, compatibility requirements, and vendor guidance before making production changes.