5.1
MEDIUM CVSS 4.0
CVE-2026-45021
Kuma: Default kuma-cp leaks admin token cross-origin via CORS wildcard + LocalhostIsAdmin
Description

Kuma is a modern Envoy-based service mesh that can run on every cloud across both Kubernetes and VMs. Prior to 2.7.25, 2.9.15, 2.11.13, 2.12.10, and 2.13.5, the default kuma-cp config leaks the admin bootstrap token and signing keys to any webpage the operator visits while the control plane is reachable from their browser. CorsAllowedDomains: [".*"] reflects any Origin, and LocalhostIsAdmin: true promotes requests from 127.0.0.1 to mesh-system:admin. A cross-origin fetch() from a malicious page returns the admin JWT and signing material. This vulnerability is fixed in 2.7.25, 2.9.15, 2.11.13, 2.12.10, and 2.13.5.

INFO

Published Date :

May 28, 2026, 6:16 p.m.

Last Modified :

May 28, 2026, 6:56 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-45021 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 4.0 MEDIUM [email protected]
Solution
Update Kuma to a fixed version to prevent admin token and key leakage.
  • Update Kuma to version 2.7.25 or later.
  • Update Kuma to version 2.9.15 or later.
  • Update Kuma to version 2.11.13 or later.
  • Update Kuma to version 2.12.10 or later.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-45021 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-45021 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-45021 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-45021 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    May. 28, 2026

    Action Type Old Value New Value
    Added Description Kuma is a modern Envoy-based service mesh that can run on every cloud across both Kubernetes and VMs. Prior to 2.7.25, 2.9.15, 2.11.13, 2.12.10, and 2.13.5, the default kuma-cp config leaks the admin bootstrap token and signing keys to any webpage the operator visits while the control plane is reachable from their browser. CorsAllowedDomains: [".*"] reflects any Origin, and LocalhostIsAdmin: true promotes requests from 127.0.0.1 to mesh-system:admin. A cross-origin fetch() from a malicious page returns the admin JWT and signing material. This vulnerability is fixed in 2.7.25, 2.9.15, 2.11.13, 2.12.10, and 2.13.5.
    Added CVSS V4.0 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
    Added CWE CWE-346
    Added CWE CWE-942
    Added Reference https://github.com/kumahq/kuma/commit/8fefa8595d44eb68d922405702ed7a0826322907
    Added Reference https://github.com/kumahq/kuma/pull/16416
    Added Reference https://github.com/kumahq/kuma/pull/16423
    Added Reference https://github.com/kumahq/kuma/pull/16424
    Added Reference https://github.com/kumahq/kuma/pull/16425
    Added Reference https://github.com/kumahq/kuma/pull/16426
    Added Reference https://github.com/kumahq/kuma/pull/16427
    Added Reference https://github.com/kumahq/kuma/security/advisories/GHSA-3vcp-chfh-f6r2
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.