CVE-2026-56191

critical Microsoft
CVSS v3 Base Score
10.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS Score
0.7%
Exploitation probability in 30 days
Top 51% most likely to be exploited
Attack Characteristics
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Confidentiality
High
Integrity
High
Availability
High
Published: July 24, 2026 (45 days ago)
Last Modified: July 29, 2026
Vendor: Microsoft
Source: NVD

Description

Improper authentication in Microsoft Exchange Online allows an unauthorized attacker to perform tampering over a network.

CWE

CWE-287

Affected Products

microsoft exchange online

References

🔗 msrc.microsoft.com