Vulnerability · Published Apr 8, 2026 · Assigned by GitHub_M

CVE-2026-39429kcp's cache server is accessible without authentication or authorization checks

High 8.2

In plain English

A high-severity missing authorization in kcp from kcp-dev. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.2High

Exploit odds (30 days)0.4%top 61.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/kcp-dev/kcp	0.30.3	GHSA-3j3q-wp9x-585p
Go	github.com/kcp-dev/kcp	0.29.3	GHSA-3j3q-wp9x-585p
Go	github.com/kcp-dev/kcp	0.29.3, 0.30.3	GO-2026-5088

Affected products (as reported)

Vendor	Product	Versions
kcp-dev	kcp	>= 0.30.0, < 0.30.3< 0.29.3

Weakness: CWE-862, CWE-302 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

References

https://github.com/kcp-dev/kcp/security/advisories/GHSA-3j3q-wp9x-585p x_refsource_CONFIRM
https://github.com/kcp-dev/kcp/releases/tag/v0.29.3 x_refsource_MISC
https://github.com/kcp-dev/kcp/releases/tag/v0.30.3 x_refsource_MISC