JujuApplication · Canonical
CVE-2026-4370
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe Juju controller's Dqlite database cluster lacks TLS client certificate validation, allowing any node with network access to join the cluster without authentication. An unauthenticated attacker can exploit this to gain full read/write access to the entire database.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
JujuApplication
>= 3.2.0, < 3.6.20>= 4.0, < 4.0.5CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Juju versionRun 'juju version' on the controller machine or check via 'juju controller-models' output. Alternatively, check package manager: 'snap list juju' or 'apt list --installed | grep juju'Affected if Version is >= 3.2.0 and < 3.6.20, OR >= 4.0 and < 4.0.5
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Confirm Dqlite is in useJuju controllers use Dqlite by default. Check for Dqlite process: 'ps aux | grep dqlite' or check if port 17017 is listening: 'ss -tlnp | grep 17017' or 'netstat -tlnp | grep 17017'Affected if Dqlite is running and listening on port 17017 (the default Dqlite port)
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Verify network exposure of Dqlite portCheck if port 17017 is exposed to untrusted networks: 'ss -tlnp | grep 17017' or 'iptables -L -n | grep 17017'. Check firewall rules and cloud security groups for inbound rules allowing traffic on port 17017 from non-cluster IPsAffected if Port 17017 is accessible from networks other than the trusted cluster member IPs
You are affected if your Juju version falls within the vulnerable range AND Dqlite is active AND the Dqlite port (17017) is exposed to untrusted network segments.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped3.6.204.0.5
Upgrade Juju to version 3.6.20 or later, or 4.0.5 or later to resolve the TLS authentication bypass. As a temporary control, restrict network access to the Dqlite port.
Juju 3.6.20+ or 4.0.5+ (depending on which major version line you are on)
- Identify the currently installed Juju version using `juju version`
- If running Juju 3.x (version >= 3.2.0 and < 3.6.20), upgrade to version 3.6.20 or later by following the official Juju upgrade documentation
- If running Juju 4.x (version >= 4.0.0 and < 4.0.5), upgrade to version 4.0.5 or later by following the official Juju upgrade documentation
- After upgrade, verify the new version is running using `juju version`
- Ensure the Dqlite cluster is functioning properly post-upgrade
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Juju
Scoped from the published advisory
- Consultation4.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,304.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-4370 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-4370 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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