Quick answers
- Is CVE-2026-42827 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-42827 being exploited in the wild.
- How severe is CVE-2026-42827?
- Medium severity, with a CVSS score of 6.5, published 22 May 2026.
- Which products and versions are affected?
- Microsoft M365 Copilot.
- Is there a fix for CVE-2026-42827?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-42827 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-42827?
- Check whether you run Microsoft M365 Copilot. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A command injection vulnerability (CWE-77) exists in Microsoft M365 Copilot due to improper neutralization of special elements used in commands. An unauthenticated attacker can exploit this over the network, though the CVSS vector indicates that user interaction is required (UI:R). Successful exploitation allows for unauthorized information disclosure (Confidentiality: High), potentially leaking sensitive data processed by the Copilot service. The vulnerability is specific to the M365 Copilot hosted service environment.
Affected products
- Microsoft M365 Copilot
Timeline
- 2026-05-22: advisory: Initial advisory published by Microsoft and NVD.