---
id: CVE-2026-72923
title: >-
  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
summary: >-
  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 Microso…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
  - CWE-770
vendor: Microsoft
product: OpenApi.YamlReader
affected:
  - OpenApi.YamlReader >= 2.0.0-preview.11 < 2.12.0
  - OpenApi.YamlReader >= 3.0.0 < 3.10.0
  - OpenApi.Readers < 1.6.30
patched:
  - Microsoft.OpenApi.YamlReader 3.10.0
  - Microsoft.OpenApi.YamlReader 2.12.0
  - Microsoft.OpenApi.Readers 1.6.30
published: '2026-09-08'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T21:17:39.323'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-72923'
references:
  - url: >-
      https://github.com/microsoft/OpenAPI.NET/commit/1f9aea9bdcbf4066b59ce33b3bd8f97ed9cb4766
    label: security-advisories@github.com
  - url: >-
      https://github.com/microsoft/OpenAPI.NET/commit/21793261d6860fb6e607b71fd95c0bd320724764
    label: security-advisories@github.com
  - url: >-
      https://github.com/microsoft/OpenAPI.NET/commit/4db9af07d112cdf45170b7a946f956ffe74fa14e
    label: security-advisories@github.com
  - url: >-
      https://github.com/microsoft/OpenAPI.NET/security/advisories/GHSA-7pxr-59rr-hqj2
    label: security-advisories@github.com
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-72923'
  - url: 'https://github.com/microsoft/OpenAPI.NET/pull/3000'
  - url: 'https://github.com/microsoft/OpenAPI.NET/pull/3005'
  - url: 'https://github.com/microsoft/OpenAPI.NET/pull/3020'
  - url: 'https://github.com/microsoft/OpenAPI.NET/releases/tag/v1.6.30'
  - url: 'https://github.com/microsoft/OpenAPI.NET/releases/tag/v2.12.0'
  - url: 'https://github.com/microsoft/OpenAPI.NET/releases/tag/v3.10.0'
  - url: 'https://github.com/advisories/GHSA-7pxr-59rr-hqj2'
tags:
  - nvd
  - cve.org
  - ghsa
  - nuget
epss: 0.01895
epssPercentile: 0.7951
aliases:
  - GHSA-7pxr-59rr-hqj2
ecosystem: nuget
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-08T17:36:59.117131Z'
ingestedAt: '2026-09-08T19:08:49.624Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-72923)

Affected packages:

- `Microsoft.OpenApi.YamlReader >= 3.0.0, < 3.10.0`
- `Microsoft.OpenApi.YamlReader >= 2.0.0-preview.11, < 2.12.0`
- `Microsoft.OpenApi.Readers < 1.6.30`

Patched in:

- `Microsoft.OpenApi.YamlReader 3.10.0`
- `Microsoft.OpenApi.YamlReader 2.12.0`
- `Microsoft.OpenApi.Readers 1.6.30`

Source: https://github.com/advisories/GHSA-7pxr-59rr-hqj2