CVE-2026-41090
Microsoft 365 Copilot has a critical command‑injection flaw that lets an attacker run arbitrary commands on the service. The vulnerability can be triggered over the network and requires the victim to interact with the application. If exploited, the attacker can modify or delete data.
No official fix yet. If none appears within 45 days of first tracking, this entry is removed automatically.
Who is affected
Microsoft 365 Copilot users, especially organizations that have enabled the Copilot feature in their Microsoft 365 environment.
Real-world impact
An attacker could run arbitrary commands on the Microsoft Copilot service, allowing them to tamper with data, modify configurations, or potentially disrupt the service.
Why this severity
The CVSS score of 9.3 reflects that the flaw can be exploited remotely (AV:N), needs only a simple action (AC:L), does not require any user privileges (PR:N), and requires the victim to use the interface (UI:R). The vulnerability changes the scope of the affected component (S:C) and can cause high confidentiality and integrity damage (C:H, I:H).
What to do about it
No official fix or mitigation is documented in the sources yet. Monitor the vendor advisory and apply the patch as soon as it is released.
No fix documented in sources
Timeline
- May 22, 2026 · May 22, 2026PublishedDisclosed and added to the National Vulnerability Database.
- Jul 23, 2026 · 12d agoAdvisory updatedThe NVD record was last revised.
How it’s attacked
References & advisories
- msrc.microsoft.com/update-guide/vulnerability/…vendor advisory