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TI-2026-70574 Aliases CVE-2026-108586GHSA-w2j7-xxh9-9q67

1MCP Agent OAuth tag-scope bypass via negated tag filter

Priority LOW 23CWE-863Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
Low · Low · None
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-863.

Summary

1MCP Agent (@1mcp/agent) from 0.20.0 through 0.39.0 contains an incorrect authorization flaw (CWE-863) in its OAuth tag-scope enforcement. An authenticated client holding a single-tag token can use a negated advanced tag filter to list and invoke tools on backend MCP servers outside its granted scopes. The attack needs low-privilege access over the network and no user interaction.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0019 8th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
1mcp-app@1mcp/agent0.20.0 – 0.39.0—No fix listedCNA
  • @1mcp/agent Vendor1mcp-app Affected 0.20.0 – 0.39.0 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for @1mcp/agent.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-11 Threatist record created from CVE-2026-108586
  2. 2026-10-11 Alias added: GHSA-w2j7-xxh9-9q67
  3. 2026-10-13 CISA SSVC decision points changed
  4. 2026-11-06 Affected versions changed · Red Hat
  5. 2026-11-06 CVSS score added · Red Hat

References

Advisory 1

Other 3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences