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CVE-2026-102503: Google SAM allows unauthenticated access via /libp2p-http

CVE-2026-102503 · published 23 days ago

Summary

Versions 0.1.0-alpha.1 and 0.1.0-alpha.2 of Google’s open‑source Agent Mesh let any remote peer call backend services without proving its identity. This can let attackers bypass policy checks and interact with command servers, internal APIs, or AI inference endpoints. Upgrade to version 0.1.0-alpha.3 or newer to restore proper authentication and authorization.

What to do

Update google sam to version 0.1.0-alpha.3 or later.

Affected software

Vendor	Product	Affected versions
google	sam	< 0.1.0-alpha.3

Original advisory text

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

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.

References

https://github.com/google/sam/releases/tag/v0.1.0-alpha.3 Vendor Advisory
https://github.com/google/sam/commit/433bc99d2a2c10071167bf22acc2c930a12e64e1 Patch
https://github.com/google/sam/security/advisories/GHSA-r6hp-67wp-c7jx Vendor Advisory
https://github.com/google/agentmesh/security/advisories/GHSA-r6hp-67wp-c7jx Exploit
https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-1025... Vendor Advisory
https://nvd.nist.gov/vuln/detail/CVE-2026-102503 Vendor Advisory

Fix within

Internet-facing 3 days

Internal 60 days

Not known to be exploited
Can be exploited automatically
Gives an attacker full control

Severity

9.9 Critical

Exploitation

<1% chance of attack within 30 days

Type

CWE-306Missing Authentication for Critical Function

CWE-862Missing Authorization

Timeline

Published19 Oct 2026

Updated8 Nov 2026

First seen19 Oct 2026

Sources

CVE-2026-102503 · NVD

CVE-2026-102503 · MITRE

CVE-2026-102503 · OSV

GHSA-r6hp-67wp-c7jx · GHSA

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