vulnerability / NVI-00012155 / Revision 3
Microsoft.OpenApi.YamlReader vulnerable to denial of service via YAML alias expansion
GitHub lists this reviewed advisory for Microsoft.OpenApi.YamlReader, Microsoft.OpenApi.YamlReader, Microsoft.OpenApi.Readers. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
7.5 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
1.845%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.79048. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
Microsoft.OpenApi.YamlReader
source listed>= 3.0.0, < 3.10.0
### Impact A small YAML OpenAPI document containing nested anchors and aliases can cause uncontrolled resource consumption in Microsoft.OpenApi.YamlReader and Microsoft.OpenApi.Readers. The issue affects OpenAPI document parsing through the public YAML reader APIs and can cause the parsing process to allocate excessive memory and terminate through out-of-memory conditions. ## Affected versions ### Microsoft.OpenApi.YamlReader * `>= 2.0.0-preview.11, = 3.0.0, < 3.10.0` ### Microsoft.OpenApi.Readers * `< 1.6.30` ### Patches * For the 1.X major version, versions 1.6.30 and above are patched. * For the 2.X major version, versions 2.12.0 and above are patched. * For the 3.X major version, versions 3.10.0 and above are patched. ## Impact Applications, CLIs, developer tools, or services that parse untrusted YAML OpenAPI documents in-process may be terminated by a crafted YAML document containing nested anchors and aliases. The impact is availability/process termination only. This report does not claim remote code execution, authentication bypass, credential exposure, privilege escalation, data exposure, or Microsoft hosted service impact. ## Details Microsoft.Op
Microsoft.OpenApi.YamlReader
source listed>= 2.0.0-preview.11, < 2.12.0
### Impact A small YAML OpenAPI document containing nested anchors and aliases can cause uncontrolled resource consumption in Microsoft.OpenApi.YamlReader and Microsoft.OpenApi.Readers. The issue affects OpenAPI document parsing through the public YAML reader APIs and can cause the parsing process to allocate excessive memory and terminate through out-of-memory conditions. ## Affected versions ### Microsoft.OpenApi.YamlReader * `>= 2.0.0-preview.11, = 3.0.0, < 3.10.0` ### Microsoft.OpenApi.Readers * `< 1.6.30` ### Patches * For the 1.X major version, versions 1.6.30 and above are patched. * For the 2.X major version, versions 2.12.0 and above are patched. * For the 3.X major version, versions 3.10.0 and above are patched. ## Impact Applications, CLIs, developer tools, or services that parse untrusted YAML OpenAPI documents in-process may be terminated by a crafted YAML document containing nested anchors and aliases. The impact is availability/process termination only. This report does not claim remote code execution, authentication bypass, credential exposure, privilege escalation, data exposure, or Microsoft hosted service impact. ## Details Microsoft.Op
Microsoft.OpenApi.Readers
source listed< 1.6.30
### Impact A small YAML OpenAPI document containing nested anchors and aliases can cause uncontrolled resource consumption in Microsoft.OpenApi.YamlReader and Microsoft.OpenApi.Readers. The issue affects OpenAPI document parsing through the public YAML reader APIs and can cause the parsing process to allocate excessive memory and terminate through out-of-memory conditions. ## Affected versions ### Microsoft.OpenApi.YamlReader * `>= 2.0.0-preview.11, = 3.0.0, < 3.10.0` ### Microsoft.OpenApi.Readers * `< 1.6.30` ### Patches * For the 1.X major version, versions 1.6.30 and above are patched. * For the 2.X major version, versions 2.12.0 and above are patched. * For the 3.X major version, versions 3.10.0 and above are patched. ## Impact Applications, CLIs, developer tools, or services that parse untrusted YAML OpenAPI documents in-process may be terminated by a crafted YAML document containing nested anchors and aliases. The impact is availability/process termination only. This report does not claim remote code execution, authentication bypass, credential exposure, privilege escalation, data exposure, or Microsoft hosted service impact. ## Details Microsoft.Op
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-7pxr-59rr-hqj2 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-72923 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 3 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.