What’s Vulnerable › Vulnerabilities

CVE-2026-102503: Missing Authentication on /libp2p-http Ingress in Google OSS Agent Mesh (SAM)

• Severity: critical (CVSS 9.3 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-19 · updated 2026-10-19
• Weakness: CWE-306

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.

Affected products

• Google SAM: from 0.1.0-alpha.1 before 0.1.0-alpha.3 — fixed in 0.1.0-alpha.3

How to fix

Upgrade to a fixed version: Google SAM 0.1.0-alpha.3. Check the vendor advisory for mitigations.

References

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

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