---
title: "CVE-2026-72923: Microsoft OpenApi - Denial of Service"
description: "Microsoft.OpenApi.YamlReader 2.0.0-preview.11 to 2.12.0, 3.0.0 to 3.10.0, and Microsoft.OpenApi.Readers prior to 1.6.30 contain a denial of service caused by uncontrolled resource consumption during YAML-to-JSON conversion of nested anchors and aliases, letting attackers cause out-of-memory conditions, exploit requires crafted YAML document."
url: https://panop.io/threat-heartbeat/CVE-2026-72923/
---

# CVE-2026-72923 Microsoft OpenApi - Denial of Service

Microsoft.OpenApi.YamlReader 2.0.0-preview.11 to 2.12.0, 3.0.0 to 3.10.0, and Microsoft.OpenApi.Readers prior to 1.6.30 contain a denial of service caused by uncontrolled resource consumption during YAML-to-JSON conversion of nested anchors and aliases, letting attackers cause out-of-memory conditions, exploit requires crafted YAML document.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

1.20% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-72923)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Published

8 September 2026

Updated

15 October 2026

Weakness

[CWE-400](https://cwe.mitre.org/data/definitions/400.html)

## Vendor fix

Update to Microsoft.OpenApi.YamlReader 2.12.0, 3.10.0 or Microsoft.OpenApi.Readers 1.6.30 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-72923](https://nvd.nist.gov/vuln/detail/CVE-2026-72923)
- [https://github.com/microsoft/OpenAPI.NET/commit/21793261d6860fb6e607b71fd95c0bd320724764](https://github.com/microsoft/OpenAPI.NET/commit/21793261d6860fb6e607b71fd95c0bd320724764)
- [https://github.com/microsoft/OpenAPI.NET/commit/4db9af07d112cdf45170b7a946f956ffe74fa14e](https://github.com/microsoft/OpenAPI.NET/commit/4db9af07d112cdf45170b7a946f956ffe74fa14e)
- [https://github.com/microsoft/OpenAPI.NET/security/advisories/GHSA-7pxr-59rr-hqj2](https://github.com/microsoft/OpenAPI.NET/security/advisories/GHSA-7pxr-59rr-hqj2)
- [https://github.com/microsoft/OpenAPI.NET/commit/1f9aea9bdcbf4066b59ce33b3bd8f97ed9cb4766](https://github.com/microsoft/OpenAPI.NET/commit/1f9aea9bdcbf4066b59ce33b3bd8f97ed9cb4766)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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