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OpenAdvisories
High MSRC-CVE-2026-45455 1 CVE

Microsoft Excel Information Disclosure Vulnerability

Published Jun 9, 2026 · Updated Jun 19, 2026 · Revision 2

Vendor: Microsoft

Summary

Impact: Information Disclosure. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.

Details

According to the CVSS metrics, successful exploitation of this vulnerability could lead to some loss of confidentiality (C:L),but lead to no loss of availability (A:N) and integrity (I:N)? What does that mean for this vulnerability?
An attacker who successfully exploited the vulnerability could view some sensitive information (Confidentiality) but not all resources within the impacted component may be divulged to the attacker. The attacker cannot make changes to disclosed information (Integrity) or limit access to the resource (Availability).

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.

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?
No, the Preview Pane is not 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.

Security updates
16.0.10417.20137 — https://support.microsoft.com/help/5002875
https — https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
16.110.26061317 — https://go.microsoft.com/fwlink/p/?linkid=831049
16.0.5556.1001 — https://support.microsoft.com/help/5002877
16.110.26061317 — https://www.microsoft.com/en-us/microsoft-365/mac/microsoft-365-for-mac?msockid=35f9adb0e74b61392038b90de6fe608c

Vulnerabilities 1

Revision history

  1. #2

    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](https://go.microsoft.com/fwlink/p/?linkid=831049) for more information and download links.

  2. #1

    Information published.

References