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01 Record

CVE-2026-48529

GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion

MediumPUBLISHEDCNA: GitHub_M
CNA base score6.0 CVSS v3.xCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L

02 Description

GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion

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.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • 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
0.16% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 5.7% of scored records. A rank, not a probability.
NVD base score
6.0 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L
NVD analysis status
Deferred. 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
2026-06-26 16:33Z4 MO AGO
Last updated
2026-06-27 02:43Z4 MO AGO
Reserved
2026-05-21
Assigning CNA
GitHub_M
Record state
PUBLISHED
Severity
Medium (CVSS 6.0)
CNA CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L
Weaknesses
  • CWE-284Improper Access ControlPillar
Data version
5.2
Document digest
f5a5b07169c025ddeec0e69ab21600eee160a4e226c7c8e8b980f2dcc0eeef2d

05 Affected products

VendorProductVersionsPlatforms
githubgithub-mcp-server>= 0.22.0, < 1.1.2—

06 References