RCE in Microsoft 365 Copilot

CVE-2026-41090

Improper neutralization of special elements used in a command ('command injection') in Microsoft Copilot allows an unauthorized attacker to perform tampering over a network.

Vulnerability class: Command Injection (OS Command Injection)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.008 (54.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 54.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-41090: held from 0.004 to 0.008.

EPSS over last 30 days · oldest: 0.004 · newest: 0.008 · change: +0.003

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-41090?
CVE-2026-41090 is a critical-severity vulnerability in Microsoft 365 Copilot, classified under Command Injection. CVSS score: 9.3/10. Published 2026-05-22.
How severe is CVE-2026-41090?
Critical severity. CVSS v3 base score is 9.3 out of 10.