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[ CVE-2026-102503 · Published 19 Oct 2026 ]

Vulnerability in Google SAM

CVSS 9.3 EPSS <1%No fix listed yet

[ Why it matters ]Priority signals

  • Public proof-of-concept exploit exists (CISA SSVC)
  • Critical severity: CVSS 9.3

[ Description ]Official description

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.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References