CVE-2026-45021CWE-346CWE-942

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

Medium · published May 28, 2026

CVSS v4.0
5.1
EPSS
0%
Percentile
21.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
5.1 · MEDIUM
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
EPSS
0.00298 · 21.3th percentile
Weaknesses
CWE-346 · Origin Validation Error; CWE-942 · Permissive Cross-domain Security Policy with Untrusted Domains
Published
2026-05-28T17:45Z
EPSS history
Timeline
  • 28 MAY 17:45Z
    Kuma: Default kuma-cp leaks admin token cross-origin via CORS wildcard + LocalhostIsAdmin
    cvelistv5