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AIKIDO-2026-627503

Microsoft.OpenApi.Readers is vulnerable to Uncontrolled Resource Consumption

Uncontrolled Resource ConsumptionGHSA-7pxr-59rr-hqj2 Published Aug 14, 2026

53

Medium Risk

This Affects:

DOTNETMicrosoft.OpenApi.Readers
0.0.1 - 1.6.29
Fixed in 1.6.30
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TL;DR

The legacy reader bundles a YAML parser that expands anchors and aliases without bounding nesting depth or the number of materialized nodes. A small crafted YAML OpenAPI document using recursive alias expansion (a billion laughs payload) forces the converter to allocate an exponentially large node graph. Parsing such a document through the public reader APIs exhausts process memory and can terminate the host process. The fix enforces maximum nesting-depth and node-count limits and surfaces a diagnostic error instead of continuing expansion.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range and your application parses untrusted or externally influenced YAML OpenAPI documents through the reader APIs.

Background info

Microsoft.OpenApi.Readers is vulnerable to Uncontrolled Resource Consumption in versions 0.0.1 - 1.6.29.

How to fix this

Upgrade the Microsoft.OpenApi.Readers library to the patch version.