Critical 9.3Published Oct 18, 2026

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

Updated under an hour ago (Oct 28, 2026, 4:30 AM ET)

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EPSS puts the chance of exploitation in the next 30 days at 0.43%, higher than 37% of scored CVEs.

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Exploited in the last 30 days

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.

CVSS: 9.3 CRITICAL (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness (CWE): CWE-306, CWE-862
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.43% (percentile 37)
Assigned by: Google
NVD analysis: Awaiting Analysis
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 18, 2026

Affected products

Affected products

Google SAM google:sam (from the name)	from 0.1.0-alpha.1 before 0.1.0-alpha.3	CNA record

References

References

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

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.