Origin Validation Error in .NET Products by Microsoft
CVE-2026-58649

6.5MEDIUM

Key Information:

Vendor

Microsoft
Status
.net 10.0
.net 11.0
.net 8.0
.net 9.0
Vendor
CVE Published:
8 September 2026

What is CVE-2026-58649?

A vulnerability exists in .NET due to an origin validation error, which could be exploited by an unauthorized attacker to disclose sensitive information over a network. This flaw highlights the importance of robust validation checks to prevent unauthorized access and data leaks. Microsoft has acknowledged this issue and provides resources for developers to understand the implications and apply necessary patches.

Affected Version(s)

.NET 10.0 10.0.0 < 10.0.111, 10.0.400

.NET 11.0 11.0.0 < 11.0 RC1

.NET 8.0 8.0.0 < 8.0.130, 8.0.424

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.