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Fencer Vulns
medium 5.3

CVE-2026-18675 json

Kong Mesh: control plane denial of service via a malformed dataplane token with a non-string JWT kid

published 2026-08-12 2 mo ago modified 2026-10-23 16 d ago also EUVD-2026-57421

cvss
5.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 46%
public exploits
0
none known

Summary

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.

Patch / fix

  • Kong Inc. Kong Mesh 2.7.29, 2.9.19, 2.11.18, 2.12.14, 2.13.10, 2.14.2

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.56% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.3 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CNA 4.0 5.3 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • Kong Inc. Kong Mesh

Classification

Weakness
  • CWE-248 Uncaught Exception
  • CWE-704 Incorrect Type Conversion or Cast

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.