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CVE-2026-48529

MEDIUM Exploitation: PoC
6.0
CVSS 3.1
Description
GitHub MCP Server is GitHub's official MCP Server. From 0.22.0 until 1.1.2, when running in HTTP mode with --lockdown-mode enabled, the RepoAccessCache is implemented as a process-global singleton initialized with the first authenticated user's GraphQL client. All subsequent requests from different users share this singleton and their lockdown-related GraphQL queries are executed using the first user's credentials. The singleton is never updated to reflect later users' tokens. This vulnerability is fixed in 1.1.2.

Metadata

CVE ID
CVE-2026-48529
State
PUBLISHED
Assigner
GitHub_M
Reserved
2026-05-21 16:18 UTC
Published
2026-06-26 16:33 UTC
Last updated
2026-06-27 02:43 UTC
Primary CWE
CWE-284
CWE-284: Improper Access Control
Vendor / Product
github / github-mcp-server
Sources
cve.org  ·  NVD

Severity & Metrics

6.0 MEDIUM CVSS 3.1
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L
SSVC — CISA Coordinator
Exploitation
PoC
Automatable
no
Tech. Impact
partial
Affected products (1)
VendorProductPlatformVersions
github github-mcp-server — >= 0.22.0, < 1.1.2
Weakness (CWE)
CWESourceDescription
CWE-284 cna CWE-284: Improper Access Control
CVSS scores (1)
ScoreSeverityVersionSourceVector
6.0 MEDIUM 3.1 cna CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L
References (1)
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