What is CVE-2026-81954?

CVE-2026-81954 is a high-severity vulnerability in Microsoft 365 Apps, classified under Use After Free. CVSS score: 7.8/10. Published 2026-09-08.

How severe is CVE-2026-81954?

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

Use After Free in Microsoft 365 Apps

CVE-2026-81954

Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

Vulnerability class: Use-After-Free

Published 2026-09-08 · last modified 2026-09-17.

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.

EPSS exploit prediction

EPSS: 0.005 (39.5th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-416 — Use After Free

References

Microsoft Excel Remote Code Execution Vulnerability (vendor-advisory, Patch, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-81954?: CVE-2026-81954 is a high-severity vulnerability in Microsoft 365 Apps, classified under Use After Free. CVSS score: 7.8/10. Published 2026-09-08.
How severe is CVE-2026-81954?: High severity. CVSS v3 base score is 7.8 out of 10.