CVE-2026-102503CWE-306CWE-862broken-access-control

CVE-2026-102503

published October 19, 2026

CVSS
9.3
EPSS
0%
Percentile
27.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS
9.3 · NONE
CVSS v4.0
9.3 · 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
EPSS
0.00348 · 27.2th percentile
Weaknesses
CWE-306 · Missing Authentication for Critical Function; CWE-862 · Missing Authorization
Published
2026-10-19T07:16Z
References (4)
https://github.com/google/sam/commit/433bc99d2a2c10071167bf22acc2c930a12e64e1 · [email protected]https://github.com/google/sam/releases/tag/v0.1.0-alpha.3 · [email protected]https://github.com/google/sam/security/advisories/GHSA-r6hp-67wp-c7jx · [email protected]https://github.com/google/agentmesh/security/advisories/GHSA-r6hp-67wp-c7jx · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 20 OCT 03:28Z
    EPSS moved — → 0%
    epss
  • 19 OCT 02:20Z
    Missing Authentication on /libp2p-http Ingress in Google OSS Agent Mesh (SAM)
    cvelistv5
  • 19 OCT 02:20Z
    Missing Authentication on /libp2p-http Ingress in Google OSS Agent Mesh (SAM)
    cvelistv5