CVE-2026-1237 Juju has broken CMR authorization
A malicious user can mint invalid macaroons to bypass revoked cross-model permissions, allowing unauthorized charm relations and workload access.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-1237?
CVE-2026-1237 is a low-severity authentication bypass vulnerability in Canonical juju, published on 28 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Vulnerable cross-model authorization in juju. If a charm's cross-model permissions are revoked or expire, a malicious user who is able to update database records can mint an invalid macaroon that is incorrectly validated by the juju controller, enabling a charm to maintain otherwise revoked or expired permissions. This allows a charm to continue relating to another charm in a cross-model relation, and use their workload without their permission. No fix is available as of the time of writing.
Which versions are affected by CVE-2026-1237?
3 open source packages ship an affected version, including github.com/juju/juju.
| Package | Affected | Fixed in |
|---|---|---|
github.com/juju/juju Go | All versions | None |
github.com/juju/juju Go | All versions to 0.0.0-20260127110037-9b1a0e53a4a4 | None |
github.com/juju/juju Go | All versions to 0.0.0-20260127110037-9b1a0e53a4a4 | None |
How do I fix CVE-2026-1237?
No fix published yet.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-1237 being exploited?
There is no known exploitation of CVE-2026-1237 in the wild and no public exploit code.
Sources
Also known as GHSA-j477-6vpg-6c8x, GO-2026-4388.