{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-103091", "assignerOrgId": "14ed7db2-1595-443d-9d34-6215bf890778", "state": "PUBLISHED", "assignerShortName": "Google", "dateReserved": "2026-09-30T01:36:24.048Z", "datePublished": "2026-10-19T02:24:35.225Z", "dateUpdated": "2026-10-19T02:24:35.225Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "14ed7db2-1595-443d-9d34-6215bf890778", "shortName": "Google", "dateUpdated": "2026-10-19T02:24:35.225Z"}, "title": "Insecure Default Policy and Unrestricted OIDC Enrollment in Google OSS Agent Mesh (SAM)", "datePublic": "2026-09-06T16:01:00.000Z", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-862", "description": "CWE-862 Missing Authorization", "type": "CWE"}]}, {"descriptions": [{"lang": "en", "cweId": "CWE-1188", "description": "CWE-1188 Initialization of a Resource with an Insecure Default", "type": "CWE"}]}, {"descriptions": [{"lang": "en", "cweId": "CWE-306", "description": "CWE-306 Missing Authentication for Critical Function", "type": "CWE"}]}, {"descriptions": [{"lang": "en", "cweId": "CWE-863", "description": "CWE-863 Incorrect Authorization", "type": "CWE"}]}, {"descriptions": [{"lang": "en", "cweId": "CWE-200", "description": "CWE-200 Exposure of Sensitive Information to an Unauthorized Actor", "type": "CWE"}]}], "impacts": [{"capecId": "CAPEC-180", "descriptions": [{"lang": "en", "value": "CAPEC-180 Exploiting Incorrectly Configured Access Control Security Levels"}]}, {"capecId": "CAPEC-122", "descriptions": [{"lang": "en", "value": "CAPEC-122 Privilege Abuse"}]}], "affected": [{"vendor": "Google", "product": "SAM", "packageName": "github.com/google/sam", "versions": [{"status": "affected", "version": "0.1.0-alpha.1", "lessThan": "0.1.0-alpha.9", "versionType": "semver"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "Missing Authorization (CWE-862) and Initialization of a Resource with an Insecure Default (CWE-1188) in the MCP proxy (HandleStreamPassThrough in mcp_service.go) and OIDC registration flow (GET /info and POST /register in internal/controlplane/server.go) in Google OSS Agent Mesh (SAM) versions 0.1.0-alpha.1 through 0.1.0-alpha.8 allow a remote attacker to self-enroll into the mesh and invoke arbitrary tools across all connected MCP backend nodes. Because GET /info publicly discloses OIDC configuration, POST /register auto-enrolls any valid OIDC token holder without claim filtering or ban checks, and the default policy binds sam:system:authenticated to wildcard services and targets, an attacker can obtain a mesh credential with full read, write, and execution access on backend services. Users should upgrade to version 0.1.0-alpha.9 or later, which enforces a fail-closed default policy, explicit policy-binding requirements on enrollment, and ban checks.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>Missing Authorization (CWE-862) and Initialization of a Resource with an Insecure Default (CWE-1188) in the MCP proxy (HandleStreamPassThrough in mcp_service.go) and OIDC registration flow (GET /info and POST /register in internal/controlplane/server.go) in Google OSS Agent Mesh (SAM) versions 0.1.0-alpha.1 through 0.1.0-alpha.8 allow a remote attacker to self-enroll into the mesh and invoke arbitrary tools across all connected MCP backend nodes. Because GET /info publicly discloses OIDC configuration, POST /register auto-enrolls any valid OIDC token holder without claim filtering or ban checks, and the default policy binds sam:system:authenticated to wildcard services and targets, an attacker can obtain a mesh credential with full read, write, and execution access on backend services. Users should upgrade to version 0.1.0-alpha.9 or later, which enforces a fail-closed default policy, explicit policy-binding requirements on enrollment, and ban checks.</p>"}]}], "references": [{"url": "https://github.com/google/sam/security/advisories/GHSA-cgmg-9xf6-rrgw", "tags": ["vendor-advisory"]}, {"url": "https://github.com/google/sam/releases/tag/v0.1.0-alpha.9", "tags": ["release-notes"]}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "CRITICAL", "baseScore": 9.3, "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}}], "credits": [{"lang": "en", "value": "Eli Ainhorn (Noma Security)", "type": "finder"}], "source": {"discovery": "EXTERNAL"}, "x_generator": {"engine": "Vulnogram 1.0.2"}}}}

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