Out-of-bounds read in Microsoft products - CVE-2026-78515
Published: September 9, 2026
Vulnerability identifier: #VU148233
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-78515
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to an out-of-bounds read in Microsoft Office Excel when processing an Excel file. A remote attacker can cause Excel to process an Excel file to disclose sensitive information.
The Preview Pane is an attack vector, and disclosed information may include small portions of heap memory.
Affected software
Microsoft Office for macOS
Microsoft 365 Apps for Enterprise
Microsoft Office
Microsoft 365 Apps for Enterprise
Microsoft Office
How to mitigate CVE-2026-78515
Install security update from vendor's website.
Microsoft Office for macOS - update to 16.112.26083020
Microsoft 365 Apps for Enterprise - update to 16.0.20326.20138
Microsoft Office - addressed in versions 16.0.5569.1000, 16.0.10417.20207, 16.0.14334.20906, 16.0.17932.20976
Microsoft 365 Apps for Enterprise - update to 16.0.20326.20138
Microsoft Office - addressed in versions 16.0.5569.1000, 16.0.10417.20207, 16.0.14334.20906, 16.0.17932.20976