CVE-2026-54130CWE-306

M365 Copilot Information Disclosure Vulnerability

Critical · published June 18, 2026

CVSS v3.1
9.8
EPSS
1%
Percentile
65.0
In the wild
Unconfirmed
What it is

Missing authentication for critical function in M365 Copilot allows an unauthorized attacker to disclose information over a network.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CVSS v4.0
Not supplied
EPSS
0.01084 · 65.0th percentile
Weakness
CWE-306 · Missing Authentication for Critical Function
Published
2026-06-18T21:42Z
EPSS history
Timeline
  • 18 JUN 21:42Z
    M365 Copilot Information Disclosure Vulnerability
    cvelistv5