Out-of-bounds Read in Microsoft 365 Apps

CVE-2026-81957

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

secure@microsoft.com (vendor-advisory, Patch, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-81957?: CVE-2026-81957 is a high-severity vulnerability in Microsoft 365 Apps, classified under Out-of-bounds Read. CVSS score: 7.8/10. Published 2026-09-08.
How severe is CVE-2026-81957?: High severity. CVSS v3 base score is 7.8 out of 10.