CVE-2026-108586 Details
Description
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.
A vulnerability exists in 1MCP Agent versions 0.20.0 through 0.39.0, allowing authenticated clients to bypass OAuth tag-scope enforcement. This is achieved by using negated advanced tag-filter expressions to manipulate which backend servers are accessed. Attackers with a single-tag token can exploit this to list and invoke tools on servers outside their granted scopes.
Users can update to version 0.39.3 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Oct 10, 2026CISA-ADP
Assessed Oct 13, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-863 | Incorrect Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| 1MCP Agent | >= 0.20.0, <= 0.39.0 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Oct 13, 2026 | CVE Modified | CISA-ADP |
| Oct 10, 2026 | New CVE Received | [email protected] |