High severity · published Jun 18, 2026
CVE-2026-54130
M365 Copilot Information Disclosure Vulnerability
7.5
CVSS
1.1%
EPSS
No
On KEV
Description
Missing authentication for critical function in M365 Copilot allows an unauthorized attacker to disclose information over a network.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.1% · higher than 65% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
M3
Microsoft 365 Copilot · Microsoft
All versions, or not specified · source: vendor
3C
365 Copilot · Microsoft
All versions, or not specified · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-54130
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-54130
Vendor Advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54130
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