CVE-2026-26129 HIGH

CVE-2026-26129: M365 Copilot Information Disclosure Vulnerability

Vendor Microsoft

Product Microsoft 365 Copilot's Business Chat

Weakness CWE-138

Published May 7, 2026

Last update June 9, 2026

View on NVD All CVEs

CVSS base score

7.5/10

Attack vector Network

Attack complexity Low

Privileges required None

User interaction None

Confidentiality High

Integrity None

CVSS 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

What the vulnerability does

01Description

Improper neutralization of special elements used in a command ('command injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.

Key dates

02Disclosure timeline

May 7, 2026 CVE published

June 9, 2026 Record updated

External resources

03References

NVD — National Vulnerability Database https://nvd.nist.gov/vuln/detail/CVE-2026-26129 CWE — Common Weakness Enumeration https://cwe.mitre.org/data/definitions/138.html

Related vulnerabilities

04Related CVE

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