CVE-2026-4370: Canonical Juju

Critical severity, CVSS 10.0. EPSS: 0.4% chance of exploitation in the next 30 days.

A vulnerability was identified in Juju from version 3.2.0 until 3.6.19 and from version 4.0 until 4.0.4, where the internal Dqlite database cluster fails to perform proper TLS client and server authentication. Specifically, the Juju controller's database endpoint does not validate client certificates when a new node attempts to join the cluster. An unauthenticated attacker with network reachability to the Juju controller's Dqlite port can exploit this flaw to join the database cluster. Once joined, the attacker gains full read and write access to the underlying database, allowing for total data compromise.

Affected products

• Canonical Juju: from 3.2.0, before 3.6.20 (fixed in 3.6.20); from 4.0, before 4.0.5 (fixed in 4.0.5)

Published 2026-04-01. Last modified 2026-06-17.