# CVE-2026-66785: Missing authorization in Red Hat Advanced Cluster Management for Kubernetes 2

> A malicious cluster can hijack cross-cluster traffic by publishing unvalidated network endpoints, leading to information disclosure or disruption.

- **Severity:** High 8.7 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** GHSA-37mq-728j-5q43

## What is CVE-2026-66785?

CVE-2026-66785 is a high-severity missing authorization vulnerability in Red Hat Advanced Cluster Management for Kubernetes 2, published on 20 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

A flaw was found in Submariner. This vulnerability allows a malicious cluster (spoke) to redirect network traffic from other connected clusters (peer clusters) by publishing a specially crafted network endpoint. The system fails to properly validate the network subnets provided by the malicious cluster, enabling it to declare arbitrary network ranges. Consequently, all network traffic intended for these arbitrary ranges from peer clusters will be rerouted through the attacker's tunnel, potentially leading to unauthorized information disclosure or network disruption.

Weakness: CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2026-66785?


## How do I fix CVE-2026-66785?

No fix has been published for CVE-2026-66785 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-66785 being exploited?

There is no known exploitation of CVE-2026-66785 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-66785 and fix it if it is affected.

What it is: CVE-2026-66785 is a high-severity missing authorization vulnerability in Red Hat Advanced Cluster Management for Kubernetes 2, published on 20 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-66785 in the wild and no public exploit code.

Affected product: Red Hat Advanced Cluster Management for Kubernetes 2. 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-2026-66785/ (Markdown: https://insights.sbomify.com/CVE-2026-66785/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-66785
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-66785
- OSV: https://osv.dev/vulnerability/CVE-2026-66785

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-66785/
Summaries are generated and may contain mistakes; the official description above is the record.