CVE-2026-72923

HighCVSS 7.5

Published: 08/09/2026(UTC)Updated: 14/10/2026(UTC)Translated: 15/10/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

High risk

1.90%

79th percentile - higher than 79% of all known CVEs

Summary

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. 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.

Risk Assessment

An attacker can supply a crafted YAML OpenAPI document that exhausts memory and terminates the application process, causing a denial of service (DoS).

Recommendation

Update Microsoft.OpenApi.Readers to 1.6.30 and Microsoft.OpenApi.YamlReader to 2.12.0 or 3.10.0, which by default bound materialization to 5,000,000 nodes and a nesting depth of 64.

Other vulnerabilities in Microsoft.OpenApi

CVE-2026-49451High
A vulnerability in the Microsoft.OpenApi library (OpenAPI.NET SDK) can cause process termination due to stack overflow when parsing an OpenAPI document with a circular schema reference. The issue affects versions from 2.0.0-preview11 to 2.7.5 and 3.5.4, confirmed for both JSON and YAML readers.

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS