PoC Index

CVE-2026-48529

MEDIUM 6.0EPSS 0.2%

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.

CVSS v3.1
6.0 MEDIUMCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L
CVSS v3.1
6.0 MEDIUMCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L
EPSS
0.21% chance of exploitation in the next 30 days, 11th percentile
Published
2026-06-26
Updated
2026-06-27

Proof-of-concept exploits (1)

References

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