CVE-2026-103091 Google OSS Agent Mesh - Broken Access Control

Google OSS Agent Mesh (SAM) 0.1.0-alpha.1 through 0.1.0-alpha.8 contains missing authorization and insecure default initialization in MCP proxy and OIDC registration flow, letting remote attackers self-enroll and execute arbitrary actions across MCP backend nodes, exploit requires valid OIDC token.

CVSS base score 9.3 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.41% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Broken Access Control
Impact
Remote Code Execution, Data Tampering, Information Disclosure
CVSS vector
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
19 October 2026
Updated
20 October 2026
Weakness
CWE-200

Vendor fix

Upgrade to version 0.1.0-alpha.9 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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