CVE-2026-102503 PUBLISHED

Missing Authentication for Critical Function (CWE-306) and Missing Authorization (CWE-862) in the /libp2p-http ingress server (StartIngressServer in cmd/sam-node/node.go) in Google OSS Agent Mesh (SAM) versions 0.1.0-alpha.1 through 0.1.0-alpha.2 allow an unauthenticated remote libp2p peer to bypass Biscuit capability policy enforcement and invoke arbitrary registered backend services (including command/stdio-backed MCP servers, A2A, and inference endpoints). While the MCP protocol stream handler enforces WithBiscuitAuth and Authorize checks, the parallel /libp2p-http ingress routes requests directly to backend service handlers without verifying a Biscuit token or mesh enrollment. Users should upgrade to version 0.1.0-alpha.3 or later.

• Yanchon918s finder

• https://github.com/google/sam/security/advisories/GHSA-r6hp-67wp-c7jx
• https://github.com/google/sam/commit/433bc99d2a2c10071167bf22acc2c930a12e64e1
• https://github.com/google/sam/releases/tag/v0.1.0-alpha.3

• CWE-306 Missing Authentication for Critical Function CWE
• CWE-862 Missing Authorization CWE

• CAPEC-115 Authentication Bypass
• CAPEC-180 Exploiting Incorrectly Configured Access Control Security Levels