# CVE-2026-12392: Canonical MAAS information exposure in metadata endpoint

Source: https://junglewise.ai/threats/cve-2026-12392-an-information-exposure-vulnerability-in-canonical-maas-prior-to  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-02. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-12392 · Severity: medium · CVSS 5.3 · Published 2026-10-02

Canonical MAAS is a data center provisioning system that deploys and manages machines. An unauthenticated attacker who knows or can guess a machine's system identifier can retrieve the RPC secret in plaintext from the metadata endpoint if the machine was deployed with the "register as rack" option enabled. Obtaining this secret allows an attacker to register unauthorized rack controllers and access sensitive BMC credentials.

Vendors: [Canonical](https://junglewise.ai/threats/vendors/canonical).

## Quick answers

**Is CVE-2026-12392 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-12392 being exploited in the wild.

**How severe is CVE-2026-12392?** Medium severity, with a CVSS score of 5.3, published 2 October 2026.

**Which products and versions are affected?** Canonical MAAS prior to 3.4.10, 3.5.14, 3.6.5, 3.7.3, and 3.8.0.

**Is there a fix for CVE-2026-12392?** Yes: fixed in MAAS 3.4.10, 3.5.14, 3.6.5, 3.7.3, 3.8.0. Until then: Disable the "register as rack" (install_rackd) deploy parameter until patching is completed, or disable machine deployment with this option enabled in your environment. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-12392 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-12392?** Check whether you run Canonical MAAS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in MAAS 3.4.10, 3.5.14, 3.6.5, 3.7.3, 3.8.0

Disable the "register as rack" (install_rackd) deploy parameter until patching is completed, or disable machine deployment with this option enabled in your environment.

## Technical details

An information exposure vulnerability in MAAS allows unauthenticated attackers to retrieve the RPC secret via the vendor data metadata endpoint. The attacker must know or infer the target machine's system ID (obtainable through brute force, external leaks, or by guessing the MAC address and querying the TFTP grub endpoint) and the machine must have been deployed with the "register as rack" option enabled. The exposed RPC secret enables attackers to register additional rack controllers and access BMC secrets.

## Affected products

- Canonical MAAS prior to 3.4.10, 3.5.14, 3.6.5, 3.7.3, and 3.8.0

## Timeline

- 2026-05-21: disclosed: Bug reported
- 2026-06-16: advisory: CVE-2026-12392 reserved
- 2026-10-02: patched: Advisory published; fixes available in 3.4.10, 3.5.14, 3.6.5, 3.7.3, and 3.8.0

## References

- [https://bugs.launchpad.net/maas/+bug/2153942](https://bugs.launchpad.net/maas/+bug/2153942)
- [https://github.com/canonical/maas/commit/3864ef9dca54e36e3d34d18233b87666b8ee1dc8](https://github.com/canonical/maas/commit/3864ef9dca54e36e3d34d18233b87666b8ee1dc8)

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