# CVE-2026-66795: Privilege escalation in multicluster engine for Kubernetes 2.10

> A flaw in the managedcluster-import-controller allows a privileged spoke cluster service account to escalate privileges to hub cluster-admin by submitting a malicious CSR.

- **Severity:** Critical 9.9 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **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:** 17 Aug 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-w9c6-w29v-4vp6

## What is CVE-2026-66795?

CVE-2026-66795 is a critical vulnerability in Red Hat multicluster engine for Kubernetes 2.10, published on 17 Aug 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 managedcluster-import-controller. The Certificate Signing Request (CSR) auto-approval logic improperly validates incoming CSRs, specifically by not inspecting the signer name or decoding the PEM-encoded x509 CSR. This vulnerability allows a privileged service account on a spoke cluster to submit a malicious CSR. Successful exploitation can lead to privilege escalation, enabling the attacker to obtain administrative credentials on the hub cluster.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-66795?


## How do I fix CVE-2026-66795?

No fix has been published for CVE-2026-66795 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-66795 being exploited?

There is no known exploitation of CVE-2026-66795 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-66795 and fix it if it is affected.

What it is: CVE-2026-66795 is a critical vulnerability in Red Hat multicluster engine for Kubernetes 2.10, published on 17 Aug 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-2026-66795 in the wild and no public exploit code.

Affected product: Red Hat multicluster engine for Kubernetes 2.10. 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-2026-66795/ (Markdown: https://insights.sbomify.com/CVE-2026-66795/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-66795
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-66795
- OSV: https://osv.dev/vulnerability/CVE-2026-66795

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-66795/
Summaries are generated and may contain mistakes; the official description above is the record.