CVE-2026-103091
CriticalCVSS 9.3Summary
Google OSS Agent Mesh (SAM) versions 0.1.0-alpha.1 through 0.1.0-alpha.8 contain Missing Authorization (CWE-862) and Insecure Default Initialization (CWE-1188) in the MCP proxy and OIDC registration flow. Public disclosure of OIDC configuration via GET /info and auto-enrollment of any valid OIDC token holder via POST /register without claim filtering or ban checks allow a remote attacker to self-enroll into the mesh and invoke arbitrary tools across all connected MCP backend nodes.
Risk Assessment
An attacker can obtain a mesh credential with full read, write, and execution access on backend services, leading to environment compromise and unauthorized operations.
Recommendation
Upgrade Google OSS Agent Mesh 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.
Other vulnerabilities in Google OSS Agent Mesh (SAM)
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS