Answer in brief
CVE-2026-72923 records a High severity (CVSS 7.5) vulnerability in Microsoft.OpenApi.YamlReader vulnerable to denial of service via YAML alias expansion. The current sources do not mark it as known exploited. The current feed maps microsoft/OpenAPI.NET (generic), Microsoft/OpenApi.Readers (generic), Microsoft/OpenApi.Readers (generic), Microsoft/OpenApi.YamlReader (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps microsoft/OpenAPI.NET (generic), Microsoft/OpenApi.Readers (generic), Microsoft/OpenApi.Readers (generic), Microsoft/OpenApi.YamlReader (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| microsoft/OpenAPI.NETgeneric | >=3.0.0 <3.10.0 || >=2.0.0-preview.11 <2.12.0 || <1.6.30 | 1.6.30, 3.10.0, 2.12.0 |
| Microsoft/OpenApi.Readersgeneric | >=0 <1.6.31 | 1.6.31 |
| Microsoft/OpenApi.Readersgeneric | >=0 <1.6.30 | 1.6.30 |
| Microsoft/OpenApi.YamlReadergeneric | >=2.0.0-preview.11 <2.12.2 || >=3.0.0 <3.10.2 | 2.12.2, 3.10.2 |
| Microsoft/OpenApi.YamlReadergeneric | >=2.0.0-preview.11 <2.12.0 || >=3.0.0 <3.10.0 | 2.12.0, 3.10.0 |
| Microsoft.OpenApi.Readersnuget | <1.6.30 | 1.6.30 |
| Microsoft.OpenApi.YamlReadernuget | >=3.0.0,<3.10.0 | 3.10.0 |
| Microsoft.OpenApi.YamlReadernuget | >=2.0.0-preview.11,<2.12.0 | 2.12.0 |
Published upstream
Sep 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 8, 2026
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. In Microsoft.OpenApi.Readers versions before 1.6.30 and Microsoft.OpenApi.YamlReader from 2.0.0-preview.11 through 2.11.0 and 3.0.0 through 3.9.0, parsing a YAML OpenAPI document with nested anchors and aliases can consume uncontrolled memory. SharpYaml represents aliases as shared nodes in a small directed acyclic graph, but conversion to independent OpenAPI or System.Text.Json.Nodes.JsonNode trees duplicates every aliased path; without a node-count or nesting-depth limit, N nested anchors referenced k times can require k^N materialized nodes and terminate the process through an out-of-memory condition. The fixed readers bound materialization to 5,000,000 nodes and a nesting depth of 64 by default and report an OpenApiDiagnostic error when a limit is exceeded. This vulnerability is fixed in Microsoft.OpenApi.Readers 1.6.30 and Microsoft.OpenApi.YamlReader 2.12.0 and 3.10.0.
Quoted source text, attributed separately from HOL analysis.