What is CVE-2026-26134?

CVE-2026-26134 is a high-severity vulnerability in Microsoft 365_copilot, classified under Integer Overflow or Wraparound. CVSS score: 7.8/10. Published 2026-03-10.

How severe is CVE-2026-26134?

High severity. CVSS v3 base score is 7.8 out of 10.

Use After Free in Microsoft 365_copilot

CVE-2026-26134

Integer overflow or wraparound in Microsoft Office allows an authorized attacker to elevate privileges locally.

Vulnerability class: Integer Overflow

EPSS: 0.000 (15.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

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

Affected products

Microsoft 365_copilot
Microsoft Office For Android — versions 16.0.1
Microsoft Office

Weakness classification (CWE)

CWE-190 — Integer Overflow or Wraparound
CWE-416 — Use After Free

References

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

Frequently asked questions

What is CVE-2026-26134?: CVE-2026-26134 is a high-severity vulnerability in Microsoft 365_copilot, classified under Integer Overflow or Wraparound. CVSS score: 7.8/10. Published 2026-03-10.
How severe is CVE-2026-26134?: High severity. CVSS v3 base score is 7.8 out of 10.