{"id":"CVE-2026-108586","revision":"e6d589f4951b479c8365475b07b6c2b3","records":[{"revision":"e6d589f4951b479c8365475b07b6c2b3","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-108586","aliases":[],"title":"1MCP Agent 0.20.0 through 0.39.0 OAuth Tag-Scope Bypass via Negated Tag Filter","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.","state":0,"publishedAt":"2026-10-10T16:14:10.297+00:00","modifiedAt":"2026-10-13T18:27:18.799+00:00","affected":[{"ecosystem":"https://www.npmjs.com/package/@1mcp/agent","name":"@1mcp/agent","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"1mcp-app\",\n                    \"product\": \"@1mcp/agent\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0.20.0\",\n                            \"lessThanOrEqual\": \"0.39.0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ],\n                    \"packageURL\": \"pkg:npm/%401mcp/agent\",\n                    \"collectionURL\": \"https://www.npmjs.com/package/@1mcp/agent\",\n                    \"repo\": \"https://github.com/1mcp-app/agent\"\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","score":5.3,"severity":"MEDIUM"},{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","score":5.4,"severity":"MEDIUM"}],"references":["https://hackmd.io/@haind/1mcp-negated-tag-filter-oauth-scope-bypass","https://github.com/1mcp-app/agent/blob/v0.39.0/src/sdk/legacy/transport/http/middlewares/scopeAuthMiddleware.ts#L163-L183","https://github.com/1mcp-app/agent/blob/v0.39.0/src/transport/http/routes/inspectHelpers.ts#L79-L102","https://github.com/1mcp-app/agent","https://www.vulncheck.com/advisories/1mcp-agent-0.20.0-through-0.39.0-oauth-tag-scope-bypass-via-negated-tag-filter"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-108586","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-108586","identifiers":["CVE-2026-108586"]},"retained":false,"historicalAffected":[]}],"coverage":[]}