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01 Record

CVE-2026-49451

Microsoft.OpenAPI: Circular schema references may terminate OpenAPI parsing

HighPUBLISHEDCNA: GitHub_M
CNA base score7.5 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

02 Description

Microsoft.OpenAPI: Circular schema references may terminate OpenAPI parsing

03 Exploitation and scoring

Exploitation
Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
SSVC decision
  • ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
  • AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.74% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 54.5% of scored records. A rank, not a probability.
NVD base score
7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD analysis status
Awaiting Analysis. NVD last modified this record on 2026-10-25.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-06-30 16:01Z4 MO AGO
Last updated
2026-06-30 18:58Z4 MO AGO
Reserved
2026-05-30
Assigning CNA
GitHub_M
Record state
PUBLISHED
Severity
High (CVSS 7.5)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses
Data version
5.2
Document digest
72ff5a4df9d67688b8c4936736510fa329196382445506a4430e797482d62cb2

05 Affected products

VendorProductVersionsPlatforms
microsoftOpenAPI.NET>= 2.0.0-preview11, < 2.7.5, >= 3.0.0, < 3.5.4—

06 References