Auth bypass in Canonical Juju
CVE-2026-4370
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.
Vulnerability class: Improper Certificate Validation
Published · last modified .
CVSS v3 metric
CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (33.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 33rd percentile — 33.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000
Affected products
- Canonical Juju — versions 3.2.0, 4.0
Weakness classification (CWE)
References
- github.com/juju/juju/security/advisories/GHSA-gvrj-cjch-728p (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-4370?
- CVE-2026-4370 is a critical-severity vulnerability in Canonical Juju, classified under Improper Certificate Validation. CVSS score: 10.0/10. Published 2026-04-01.
- How severe is CVE-2026-4370?
- Critical severity. CVSS v3 base score is 10.0 out of 10.