Quick answers
- Is CVE-2026-26164 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-26164 being exploited in the wild.
- How severe is CVE-2026-26164?
- High severity, with a CVSS score of 7.5, published 7 May 2026.
- Which products and versions are affected?
- Microsoft 365 Copilot All versions (Exclusively Hosted Service).
- Is there a fix for CVE-2026-26164?
- 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-2026-26164 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-26164?
- Check whether you run Microsoft 365 Copilot or Microsoft 365 Copilot Chat at an affected version. 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 exists in Microsoft 365 Copilot due to improper neutralization of special elements used in a command (CWE-74). An unauthenticated attacker can exploit this over the network without user interaction (AV:N/AC:L/PR:N/UI:N). Successful exploitation results in unauthorized information disclosure (Confidentiality: High). As an exclusively hosted service, Microsoft typically manages the remediation on the backend, though the vulnerability was officially disclosed in May 2026.
Affected products
- Microsoft 365 Copilot All versions (Exclusively Hosted Service)
Timeline
- 2026-05-07: disclosed: Initial disclosure by Microsoft Corporation
- 2026-05-07: advisory: NVD published the CVE record
- 2026-06-01: other: Description updated to clarify command injection nature