CVE-2026-39429 Details
Description
kcp is a Kubernetes-like control plane for form-factors and use-cases beyond Kubernetes and container workloads. Prior to 0.30.3 and 0.29.3, the cache server is directly exposed by the root shard and has no authentication or authorization in place. This allows anyone who can access the root shard to read and write to the cache server. This vulnerability is fixed in 0.30.3 and 0.29.3.
A vulnerability exists in KCP (Kubernetes Control Plane) versions prior to 0.30.3 and 0.29.3, where the cache server is exposed by the root shard without any authentication or authorization. This allows anyone with access to the root shard to read and write to the cache server. The vulnerability arises because the cache server is routed before any authentication or authorization checks are applied, creating a window where unauthorized access is possible.
Users can upgrade to KCP versions 0.30.3 or 0.29.3, where this vulnerability has been fixed. For deployments where the root shard is exposed to untrusted networks, it is recommended to restrict access to the cache server at the network level, or to deploy the cache server separately with its own kubeconfig and restricted network access.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 10, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/kcp-dev/kcp/releases/tag/v0.29.3 | [email protected] | Release Notes |
| https://github.com/kcp-dev/kcp/releases/tag/v0.30.3 | [email protected] | Release Notes |
| https://github.com/kcp-dev/kcp/security/advisories/GHSA-3j3q-wp9x-585p | [email protected] | ExploitMitigationVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-302 | Authentication Bypass by Assumed-Immutable Data | [email protected] |
| CWE-862 | Missing Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| kcp kcp | < 0.29.3 >= 0.30.0, < 0.30.3 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 24, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 15, 2026 | Initial Analysis | [email protected] |
| Apr 8, 2026 | New CVE Received | [email protected] |