Microsoft.OpenApi.YamlReader vulnerable to denial of service via YAML alias expansion

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

• CISA KEV Not listed.
• EPSS 0.018, the 79th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

1. 31 Oct 2026, 15:21 UTC First seen by agentprime
2. 31 Oct 2026, 15:21 UTC Confirmed by OSV

Sources

• GitHub Advisory Database: GHSA-7pxr-59rr-hqj2
• OSV: GHSA-7pxr-59rr-hqj2
• github.com/microsoft/OpenAPI.NET/security/advisories/GHSA-7pxr-59rr-hqj2
• nvd.nist.gov/vuln/detail/CVE-2026-72923
• github.com/microsoft/OpenAPI.NET/pull/3000
• github.com/microsoft/OpenAPI.NET/pull/3005
• github.com/microsoft/OpenAPI.NET/pull/3020
• github.com/microsoft/OpenAPI.NET/commit/1f9aea9bdcbf4066b59ce33b3bd8f97ed9cb4766
• github.com/microsoft/OpenAPI.NET/commit/21793261d6860fb6e607b71fd95c0bd320724764
• github.com/microsoft/OpenAPI.NET/commit/4db9af07d112cdf45170b7a946f956ffe74fa14e
• github.com/microsoft/OpenAPI.NET
• github.com/microsoft/OpenAPI.NET/releases/tag/v1.6.30
• github.com/microsoft/OpenAPI.NET/releases/tag/v2.12.0
• github.com/microsoft/OpenAPI.NET/releases/tag/v3.10.0

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.