MSRC-CVE-2026-55946 — Microsoft Copilot Information Disclosure Vulnerability

Summary

Impact: Information Disclosure. Microsoft rating: Critical. Not known to be exploited. Customer action: Not required.

Details

Why are there no links to an update or instructions with steps that must be taken to protect from this vulnerability?
This vulnerability has already been fully mitigated by Microsoft. There is no action for users of this service to take. The purpose of this CVE is to provide further transparency.
Please see Toward greater transparency: Unveiling Cloud Service CVEs for more information.

Vulnerabilities 1

Medium 6.1

CVE-2026-55946

Microsoft Copilot Information Disclosure Vulnerability

Ai command injection in Microsoft Copilot allows an unauthorized attacker to disclose information over a network.

Microsoft Microsoft Copilot

Sep 17, 2026

Revision history

2026-10-27 #2
Updated an acknowledgement. This is an informational change only.
2026-09-17 #1
Information published.

References

CVE-2026-55946 Microsoft Copilot Information Disclosure Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55946
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss