CVE-2026-18675 Kong Mesh: control plane denial of service via a malformed dataplane token with a non-string JWT kid
Unauthenticated attackers can crash the Kong Mesh control plane by sending a malformed dataplane token with a non-string JWT kid, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-18675?
CVE-2026-18675 is a medium-severity denial of service vulnerability in Kong Mesh, published on 12 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
The dataplane token validator in kuma-cp performs an unchecked Go type assertion on the JWT kid header. A token whose kid is a JSON number decodes as a float64 and triggers a runtime panic before any signature, claims, or authorization check runs.
The panic terminates the entire kuma-cp process, HTTP API, the health and readiness endpoints, and xDS. Unauthenticated access to the dataplane gRPC server can trigger the crash with a malformed token
A single request is a transient interruption; sustaining an outage requires repeated requests.
Which versions are affected by CVE-2026-18675?
How do I fix CVE-2026-18675?
No fix has been published for CVE-2026-18675 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-18675 being exploited?
There is no known exploitation of CVE-2026-18675 in the wild and no public exploit code.
Sources
Also known as GHSA-5mxq-7xq4-3vx8, GHSA-7gh2-244h-962w.