CVE-2026-103091

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.

CVSS

No CVSS.

References

Link	Resource
https://github.com/google/sam/releases/tag/v0.1.0-alpha.9
https://github.com/google/sam/security/advisories/GHSA-cgmg-9xf6-rrgw
https://github.com/google/agentmesh/security/advisories/GHSA-cgmg-9xf6-rrgw

Configurations

No configuration.

History

19 Oct 2026, 18:16

Type	Values Removed	Values Added
References		() https://github.com/google/agentmesh/security/advisories/GHSA-cgmg-9xf6-rrgw -

19 Oct 2026, 03:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-19 03:16

Updated : 2026-10-19 21:13

NVD link : CVE-2026-103091

Mitre link : CVE-2026-103091

CVE.ORG link : CVE-2026-103091

JSON object : View

Products Affected

No product.

CWE

CWE-200

Exposure of Sensitive Information to an Unauthorized Actor

CWE-306

Missing Authentication for Critical Function

CWE-862

Missing Authorization

CWE-863

Incorrect Authorization

CWE-1188

Initialization of a Resource with an Insecure Default

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