Vulnerability · Published Jun 18, 2026 · Assigned by microsoft
CVE-2026-54130M365 Copilot Information Disclosure Vulnerability
Critical 9.8
In plain English
A critical-severity missing authentication in Microsoft 365 Copilot from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 65% of all known vulnerabilities).
Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)1.1%top 34.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Missing authentication for critical function in M365 Copilot allows an unauthorized attacker to disclose information over a network.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft 365 Copilot | - |
Weakness: CWE-306 · 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
References
- M365 Copilot Information Disclosure Vulnerability vendor-advisory, patch