CVE-2026-45021 MEDIUM

CVE-2026-45021: Kuma: Default kuma-cp leaks admin token cross-origin via CORS wildcard + LocalhostIsAdmin

Vendor Kumahq
Product kuma
Weakness CWE-346 · Origin validation
Published May 28, 2026
Last update May 28, 2026

CVSS base score

5.1/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Kuma is a modern Envoy-based service mesh that can run on every cloud across both Kubernetes and VMs. Prior to 2.7.25, 2.9.15, 2.11.13, 2.12.10, and 2.13.5, the default kuma-cp config leaks the admin bootstrap token and signing keys to any webpage the operator visits while the control plane is reachable from their browser. CorsAllowedDomains: [".*"] reflects any Origin, and LocalhostIsAdmin: true promotes requests from 127.0.0.1 to mesh-system:admin. A cross-origin fetch() from a malicious page returns the admin JWT and signing material. This vulnerability is fixed in 2.7.25, 2.9.15, 2.11.13, 2.12.10, and 2.13.5.

Key dates

02Disclosure timeline

May 28, 2026 CVE published
May 28, 2026 Record updated