CVE-2026-18675
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.
What this means for your business
- FIRST's prediction model gives it a 0.4% chance of attack attempts being seen in the next 30 days, ranking above 31% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
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Scoring
- CVSS
- Not yet scored
- CVSS v4
- 5.3
- Weakness
- CWE-248
- Assigned by
- 02762ae7-200e-4b20-9b2b-a77d5b8fc4cb
Dates
- Published
- 2026-08-12
- Last modified
- 2026-08-31
- Sources
- NVD
References
- https://developer.konghq.com/mesh/changelog/
- https://github.com/kumahq/kuma/pull/17465
- https://github.com/kumahq/kuma/pull/17467
- https://github.com/kumahq/kuma/pull/17468
- https://github.com/kumahq/kuma/pull/17469
- https://github.com/kumahq/kuma/pull/17470
- https://github.com/kumahq/kuma/pull/17471
- https://github.com/kumahq/kuma/pull/17472
- https://github.com/kumahq/kuma/security/advisories/GHSA-5mxq-7xq4-3vx8