CVE-2026-72923
No exploitation reported by the sources we read.
- Published2026-09-08
- Fixed in3.10.0 · 2.12.0
- WeaknessCWE-400
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
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.
Timeline
dates in UTC- 2026-09-0818:20CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-24 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-72923?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-72923?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
OSV| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 3.x | ≥ 3.0.0, < 3.10.0 | 3.10.0 | OSV |
| 2.x | ≥ 2.0.0-preview.11, < 2.12.0 | 2.12.0 | OSV |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 1.6 | < 1.6.30 | 1.6.30 | OSV |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Microsoft.OpenApi.YamlReader to 3.10.0 · 2.12.0
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Published
- 2026-09-08
- Last Modified
- 2026-10-14
- NVD status
- Deferred
Frequently asked questions
What is CVE-2026-72923?
Is CVE-2026-72923 actively exploited?
What is the CVSS score for CVE-2026-72923?
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