CVE-2026-4370 | Improper TLS Client/Server authentication and certificate verification on Database Cluster

Exp

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.

Published: 2026-04-01 Last update: 2026-04-02 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-4370 is rated High Exploit Risk (65.7/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.38%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-4370

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-4370

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.05% 0.38% +0.33%
2 2026-06-08 0.03% 0.05% +0.02%
3 2026-04-21 — 0.03% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-4370

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
10.0 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 6.0 [email protected]

Weakness enumeration for CVE-2026-4370

GitHub Security Advisory for CVE-2026-4370

GHSA-gvrj-cjch-728p · Severity: critical · Ecosystem: go — Juju has Improper TLS Client/Server authentication and certificate verification on Database Cluster

OS Trackers for CVE-2026-4370

vendor priority summary link
ubuntu critical CVE-2026-4370 critical priority: Ubuntu including 1 source packages (juju), 4 status rows across 4 suites (jammy, noble, questing, upstream): DNE 3, needs-triage 1. https://ubuntu.com/security/CVE-2026-4370

Affected software / configurations for CVE-2026-4370

Vendor Product Version Raw CPE
canonical juju >= 3.2.0, < 3.6.20 cpe:2.3:a:canonical:juju:*:*:*:*:*:*:*:*
canonical juju >= 4.0, < 4.0.5 cpe:2.3:a:canonical:juju:*:*:*:*:*:*:*:*

References for CVE-2026-4370

cvelogic Threat Intelligence