CVE-2026-45021 Kuma: Default kuma-cp leaks admin token cross-origin via CORS wildcard + LocalhostIsAdmin
Default Kuma control plane configuration leaks admin tokens and signing keys to malicious websites via permissive CORS and localhost admin privileges.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-45021?
CVE-2026-45021 is a medium-severity vulnerability in kumahq kuma, published on 28 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Which versions are affected by CVE-2026-45021?
How do I fix CVE-2026-45021?
Upgrade to a fixed version.
Is CVE-2026-45021 being exploited?
There is no known exploitation of CVE-2026-45021 in the wild and no public exploit code.
Sources
Also known as ECHO-92ea-6473-9f56.