CVE-2026-103091
9.3CriticalPublished 19 Oct 2026 · NVD status: Received · AI triage by gemini-3.8-flash
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Impact
- Full C/I/A compromise
- Weakness
- CWE-200, CWE-306, CWE-862, CWE-863, CWE-1188
Impact
Remote attackers can self-enroll into the mesh and execute arbitrary tools across all connected backend nodes. They only need network access to the registration endpoints and a valid OIDC token from the exposed provider.
Root cause
The OIDC registration endpoint auto-enrolls any token holder without claim checks, while insecure default policies grant the authenticated role wildcard access across all backend services.
Affected systems
Google OSS Agent Mesh (SAM) 0.1.0-alpha.1 through 0.1.0-alpha.8
CVSS v4.0 · 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Fix & remediation
Upgrade to Google OSS Agent Mesh (SAM) version 0.1.0-alpha.9 or later. If you cannot patch immediately, block external network access to the GET /info and POST /register control plane endpoints.
AI-suggested. Run it in staging first and check it against the vendor advisory. Why?
NVD description
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.