CVE-2026-78501 Microsoft 365 Copilot Business Chat - Information Disclosure

Microsoft 365 Copilot Business Chat contains a command injection caused by improper neutralization of special elements in commands, letting unauthorized attackers disclose information over a network, exploit requires network access.

CVSS base score 8.6 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.48% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Information Disclosure
Impact
Information Disclosure
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Published
17 September 2026
Updated
15 October 2026
Weakness
CWE-77

Vendor fix

Update to the latest version.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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