Improper TLS Client/Server authentication and certificate verification on Database Cluster

published 2026-04-01 7 mo ago modified 2026-10-26 13 d ago also GHSA-gvrj-cjch-728p , GO-2026-5405 , EUVD-2026-17847

cvss: 10.0; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits: 0; none known

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.

Patch / fix

fixed in 1 distros 1

Canonical Juju 3.6.20, 4.0.4

govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: total
Assessed: 7 mo ago (2026-04-01)

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/juju/juju/security/advisories/GHSA-gvrj-cjch-728p referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	10.0	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
GitHub	3.1	10.0	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
go	github.com/juju/juju	<=0.0.0-20260401092550-1c1ac1922b57 all versions	no fix listed

Affected products

Canonical Juju

Classification

Weakness

CWE-295 Improper Certificate Validation
CWE-306 Missing Authentication for Critical Functionality
CWE-287 Improper Authentication
CWE-296 Improper Following of a Certificate's Chain of Trust

References

github.com /juju/juju/security/advisories/GHSA-gvrj-cjch-728p
web, exploit, vendor-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2026-4370
advisory
github.com /juju/juju
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary