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CVE-2026-108586

1MCP Agent 0.20.0 through 0.39.0 OAuth Tag-Scope Bypass via Negated Tag Filter

Published
Last modified
published
Not listed in CISA KEV
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

1MCP Agent (@1mcp/agent) 0.20.0 through 0.39.0 contains an incorrect authorization vulnerability that allows authenticated clients to bypass OAuth tag-scope enforcement using negated advanced tag-filter expressions. Attackers holding a single-tag token can send a filter like not <granted-tag> to list and invoke tools on backend MCP servers outside their granted scopes.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • 1mcp-app @1mcp/agent

    From 0.20.0 · through 0.39.0

References 5

hackmd.io

GitHub · 1mcp-app/agent

vulncheck.com