# CVE-2026-12392: RPC secret disclosure via vendor data endpoint in Canonical MAAS

> Unauthenticated attackers can retrieve RPC secrets via vendor data endpoints if machines are registered as racks, potentially bypassing security controls.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Oct 2026
- **Updated:** 4 Oct 2026
- **Also known as:** GHSA-3r9p-96x8-39gw

## What is CVE-2026-12392?

CVE-2026-12392 is a medium-severity vulnerability in Canonical MAAS, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An information exposure vulnerability in Canonical MAAS prior to versions 3.4.10, 3.5.14, 3.6.5, 3.7.3, and 3.8.0 allows an unauthenticated attacker to retrieve the RPC secret in plaintext via the vendor data metadata endpoint. If a target machine was deployed with the 'register as rack' option enabled, an attacker who obtains or infers the machine's system ID can query the preseed/metadata server to leak the secret.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-12392?


## How do I fix CVE-2026-12392?

No fix has been published for CVE-2026-12392 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-12392 being exploited?

There is no known exploitation of CVE-2026-12392 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12392 and fix it if it is affected.

What it is: CVE-2026-12392 is a medium-severity vulnerability in Canonical MAAS, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-12392 in the wild and no public exploit code.

Affected product: Canonical MAAS. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-12392/ (Markdown: https://insights.sbomify.com/CVE-2026-12392/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12392
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12392
- OSV: https://osv.dev/vulnerability/CVE-2026-12392

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12392/
Summaries are generated and may contain mistakes; the official description above is the record.