GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion_CVE-2026-48529

{
    "lastseen": "",
    "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.",
    "published": "2026-06-26T16:33:32.688Z",
    "modified": "2026-06-26T16:33:32.688Z",
    "type": "cve",
    "title": "GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion",
    "source": "GitHub_M",
    "references": "https://github.com/github/github-mcp-server/security/advisories/GHSA-pjp5-fpmr-3349",
    "id": "CVE-2026-48529",
    "bulletinFamily": "",
    "cwe": [
        "CWE-284"
    ],
    "cvelist": null,
    "sourceData": "github github-mcp-server >= 0.22.0, < 1.1.2",
    "sourceHref": "",
    "cvss": {
        "score": 6,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L",
        "version": "3.1"
    },
    "cvss2": [],
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        "baseScore": 0,
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        "confidentialityImpact": "",
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        "availabilityImpact": "",
        "cvssV3": {
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "github-mcp-server",
    "version": ">= 0.22.0, < 1.1.2",
    "vendor": "github",
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    "ai_score": 0
}