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Fencer Vulns
medium 5.1

CVE-2026-18676 json

Kong Mesh: default control plane config leaks the admin token cross-origin via a CORS wildcard and localhost admin

published 2026-05-14 5 mo ago modified 2026-10-23 16 d ago also CVE-2026-45021 , GHSA-3vcp-chfh-f6r2 , GO-2026-5102 , EUVD-2026-57423

cvss
5.1
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 22%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/kumahq/kuma 2.7.25, 2.9.15, 2.11.13, 2.12.10, 2.13.5
  • go github.com/kumahq/kuma/v2 2.7.25, 2.11.13, 2.12.10, 2.13.5
  • Kong Inc. Kong Mesh 2.7.25, 2.9.15, 2.11.13, 2.12.10, 2.13.5

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 4.0 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/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 packages

ecosystem package affected fixed in
go github.com/kumahq/kuma
<2.7.25
>=2.9.0, <2.9.15
>=2.11.0, <2.11.13
>=2.12.0, <2.12.10
>=2.13.0, <2.13.5
all versions
2.7.25
2.9.15
2.11.13
2.12.10
2.13.5
go github.com/kumahq/kuma/v2
<2.7.25
>=2.9.13, <2.11.13
>=2.12.4, <2.12.10
>=2.13.0, <2.13.5
2.7.25
2.11.13
2.12.10
2.13.5

Affected products

  • Kong Inc. Kong Mesh

Classification

Weakness
  • CWE-346 Origin Validation Error
  • CWE-942 Permissive Cross-domain Security Policy with Untrusted Domains

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.