CVE-2026-18676 Kong Mesh: default control plane config leaks the admin token cross-origin via a CORS wildcard and localhost admin
Default Kong Mesh configuration exposes admin tokens and keys to cross-origin requests, allowing attackers to steal credentials and escalate 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-2026-18676?
CVE-2026-18676 is a medium-severity vulnerability in Kong Mesh, published on 12 Aug 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
The default kuma-cp configuration in Kong Mesh reveals the admin bootstrap token and signing keys to any webpage the operator visits while the control plane is reachable from their browser. Due to a CORS misconfiguration a cross-origin fetch() from a malicious page returns the admin JWT and signing material.
Which versions are affected by CVE-2026-18676?
How do I fix CVE-2026-18676?
Apply the vendor's patch.
Is CVE-2026-18676 being exploited?
There is no known exploitation of CVE-2026-18676 in the wild and no public exploit code.
Sources
Also known as GHSA-x23j-4pcq-m26j.