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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

10.0 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS

• CVE-2026-4370: 0.39% estimated exploitation activity in the next 30 days; percentile 32.96 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Any Juju controller since 3.2.0. An attacker with only route-ability to the target juju controller Dqlite cluster endpoint may join the Dqlite cluster, read and modify all information, including escalating privileges, open firewall ports etc. This is due to not checking the client certificate, additionally, the client does not check the server's certificate (MITM attack possible), so anything goes. https://github.com/juju/juju/blob/001318f51ac456602aef20b123684f1eeeae9a77/internal/database/node.go#L312-L324 PoC Using the tool referenced below. Bootstrap a controller and show the users: Join the cluster with the first cluster member: Join the cluster with another cluster member and give the admin a new name: The admin won't like this new name: Patches Juju versions 3.6.20 and 4.0.5 are patched to fix this issue. Workarounds The strongest protection is to apply the security updates. The following mitigations have also been explored. If security updates cannot be applied, you…

Published by the source

2 Apr 2026, 00:03 UTC

Last modified by the source

8 Apr 2026, 11:57 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-gvrj-cjch-728p

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# Patch Next advisory brief: CVE-2026-4370

Advisory: Juju has Improper TLS Client/Server authentication and certificate verification on Database Cluster
IDs: CVE-2026-4370, GHSA-gvrj-cjch-728p
Record: https://patchnext.com/advisories/cve-2026-4370 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 10.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/juju/juju: affected <= 0.0.0-20260401092550-1c1ac1922b57

## Suggested inspection (read-only)
- Go github.com/juju/juju: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/juju/juju.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-gvrj-cjch-728p (GitHub-reviewed advisory GHSA-gvrj-cjch-728p lists affected ranges: Go github.com/juju/juju >=0 <=0.0.0-20260401092550-1c1ac1922b57)

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