# CVE-2026-71297: Maestro: maestro: grpc broker has no auth interceptor and client mtls is optional

> Remote attackers with valid certificates can bypass gRPC authentication to access event streams or forge agent status in Red Hat Multicluster Engine.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 5 Oct 2026
- **Updated:** 6 Oct 2026
- **Also known as:** GHSA-99qh-3h9r-vq6x

## What is CVE-2026-71297?

CVE-2026-71297 is a medium-severity missing authorization vulnerability in Red Hat Multicluster Engine for Kubernetes, published on 5 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A flaw was found in the maestro gRPC broker. This vulnerability allows a remote attacker, with a valid client certificate, to bypass authentication. This bypass enables the attacker to subscribe to other consumers' event streams, leading to unauthorized information disclosure, or to publish forged agent status, which can compromise data integrity.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-71297?


## How do I fix CVE-2026-71297?

No fix has been published for CVE-2026-71297 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-71297 being exploited?

There is no known exploitation of CVE-2026-71297 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-71297 and fix it if it is affected.

What it is: CVE-2026-71297 is a medium-severity missing authorization vulnerability in Red Hat Multicluster Engine for Kubernetes, published on 5 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-71297 in the wild and no public exploit code.

Affected product: Red Hat Multicluster Engine for Kubernetes. 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-2026-71297/ (Markdown: https://insights.sbomify.com/CVE-2026-71297/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-71297
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-71297
- OSV: https://osv.dev/vulnerability/CVE-2026-71297

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-71297/
Summaries are generated and may contain mistakes; the official description above is the record.