CVE-2026-26164

M365 Copilot Information Disclosure Vulnerability

Published May 7, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
Improper neutralization of special elements used in a command ('command injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Description Improper neutralization of special elements in output used by a downstream component ('injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network. Improper neutralization of special elements used in a command ('command injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.
Type Values Removed Values Added
First Time appeared Microsoft 365 Copilot Chat
CPEs cpe:2.3:a:microsoft:365_copilot_chat:-:*:*:*:*:*:*:*
Vendors & Products Microsoft 365 Copilot Chat
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Improper neutralization of special elements in output used by a downstream component ('injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.
Title M365 Copilot Information Disclosure Vulnerability
First Time appeared Microsoft
Microsoft 365 Copilot Business Chat
Weaknesses CWE-74
CPEs cpe:2.3:a:microsoft:365_copilot_business_chat:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft 365 Copilot Business Chat
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
microsoft
Published
Updated
Aug 10, 2026, 3:13 PM
Reserved
Feb 11, 2026, 6:33 PM
Status
Modified
Published
May 7, 2026, 10:16 PM
Modified
Oct 26, 2026, 8:10 PM