Is CVE-2026-49451 in the CISA KEV catalog?

No. CVE-2026-49451 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-49451?

CVE-2026-49451 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2026-49451?

CVE-2026-49451 has an EPSS score of 0.69% (48th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2026-49451?

No published fix for CVE-2026-49451 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

CVE & CISA-KEV Catalog

CVE-2026-49451

HIGH

7.5

CVSS v3

NVD

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. From 2.0.0-preview11 until 2.7.5 and 3.5.4, a small OpenAPI document containing a circular schema reference can cause process termination through stack overflow in Microsoft.OpenApi. The issue affects OpenAPI document parsing through public OpenAPI.NET reader APIs and has been confirmed across both JSON and YAML reader paths. This vulnerability is fixed in 2.7.5 and 3.5.4.

CWE-674

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

0.69%probability of exploitation in 30 days

48thpercentile

Moderate risk: more likely to be exploited than 48% of all known CVEs.

References

Other references1

github.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-30.