CVE-2026-56191
Microsoft Exchange Online Tampering Vulnerability
- State
- Published
- Severity
- 10.0 Critical
- Published
- Jul 24, 2026
- Updated
- Nov 1, 2026
- Reserved
- Jun 19, 2026
Description
Improper authentication in Microsoft Exchange Online allows an unauthorized attacker to perform tampering over a network.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 10.0 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C | microsoft |
Weaknesses
- CWE-287 Improper Authentication
Affected Products
| Product | Versions |
|---|---|
Microsoft Exchange OnlineMicrosoft |
|
References
- Microsoft Exchange Online Tampering Vulnerabilityvendor-advisorypatch
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