CVE-2026-102503

Critical

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.

SeverityCritical

CVSS9.3

Exploit probability—

Product

SAM

PublishedOct 19, 2026

First seenOct 19, 2026

Weakness typeCWE-306Missing authentication for critical function CWE-862Missing authorization

How to fix

Update

Google SAM0.1.0-alpha.3 or later

Patches

github.com/google/sam/commit/433bc99d2a2c10071167bf22acc2c930a12e64e1

Vendor advisories

Affected products

Product	Affected versions	Fixed in
Google SAM	0.1.0-alpha.1 ≤ v < 0.1.0-alpha.3	0.1.0-alpha.3

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