What is CVE-2026-85885?

CVE-2026-85885 is a critical-severity vulnerability in Microsoft 365 Copilot, classified under Command Injection. CVSS score: 9.9/10. Published 2026-09-17.

How severe is CVE-2026-85885?

Critical severity. CVSS v3 base score is 9.9 out of 10.

RCE in Microsoft 365 Copilot

CVE-2026-85885

Improper neutralization of special elements used in a command ('command injection') in M365 Copilot allows an authorized attacker to elevate privileges over a network.

Vulnerability class: Command Injection (OS Command Injection)

Published 2026-09-17 · last modified 2026-09-25.

CVSS v3 metric

CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (53.9th percentile), scored 2026-11-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 53.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-77 — Command Injection

References

Microsoft 365 Copilot Elevation of Privilege Vulnerability (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-85885?: CVE-2026-85885 is a critical-severity vulnerability in Microsoft 365 Copilot, classified under Command Injection. CVSS score: 9.9/10. Published 2026-09-17.
How severe is CVE-2026-85885?: Critical severity. CVSS v3 base score is 9.9 out of 10.