CVE-2026-49451
Microsoft.OpenAPI: Circular schema references may terminate OpenAPI parsing
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
The OpenAPI.NET SDK contains a useful object model for OpenAPI documents in .NET along with common serializers to extract raw OpenAPI JSON and YAML documents from the model. From 2.0.0-preview11 until 2.7.5 and 3.5.4, a small OpenAPI document containing a circular schema reference can cause process termination through stack overflow in Microsoft.OpenApi. The issue affects OpenAPI document parsing through public OpenAPI.NET reader APIs and has been confirmed across both JSON and YAML reader paths. This vulnerability is fixed in 2.7.5 and 3.5.4.
| CWE | CWE-674 |
| Vendor | microsoft |
| Product | openapi.net |
| Ecosystems | |
| Industries | TechnologyEnterprise |
| Published | Jun 30, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
microsoft / OpenAPI.NET
>= 2.0.0-preview11, < 2.7.5 >= 3.0.0, < 3.5.4