# CVE-2025-57851: Mce: privilege escalation via excessive /etc/passwd permissions

> An attacker with command execution in a Multicluster Engine container can escalate to root by modifying the group-writable /etc/passwd file.

- **Severity:** Medium 6.4 (`CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Apr 2026
- **Updated:** 1 May 2026
- **Also known as:** GHSA-87qg-cwpg-cjvw

## What is CVE-2025-57851?

CVE-2025-57851 is a medium-severity vulnerability in Red Hat Multicluster Engine for Kubernetes, published on 8 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A container privilege escalation flaw was found in certain Multicluster Engine for Kubernetes images. This issue stems from the /etc/passwd file being created with group-writable permissions during build time. In certain conditions, an attacker who can execute commands within an affected container, even as a non-root user, can leverage their membership in the root group to modify the /etc/passwd file. This could allow the attacker to add a new user with any arbitrary UID, including UID 0, leading to full root privileges within the container.

Weakness: CWE-276 (Incorrect Default Permissions)

## Which versions are affected by CVE-2025-57851?

It affects 1 product.


Products: Redhat Advanced Cluster Management for Kubernetes.

## How do I fix CVE-2025-57851?

No fix has been published for CVE-2025-57851 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-57851 being exploited?

There is no known exploitation of CVE-2025-57851 in the wild and no public exploit code.

## Other vulnerabilities in Red Hat Multicluster Engine for Kubernetes

- [CVE-2026-4740](https://insights.sbomify.com/CVE-2026-4740/): Open Cluster Management (OCM): Cross-cluster privilege escalation via improper Kubernetes client certificate renewal validation (high 8.2)
- [CVE-2023-3027](https://insights.sbomify.com/CVE-2023-3027/): Privilege escalation in RHACM (high 7.8)
- [CVE-2022-3841](https://insights.sbomify.com/CVE-2022-3841/): Server-side request forgery in RHACM (high 7.8)
- [CVE-2026-71474](https://insights.sbomify.com/CVE-2026-71474/): Insights-client-rhel9: insights-client: pull-secret bearer token written to logs on non-200 ccx response (high 7.1)
- [CVE-2026-71475](https://insights.sbomify.com/CVE-2026-71475/): Insights-client-rhel9: insights-client: spoke-controlled clusterid injected unencoded into insights api url path (medium 6.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-57851 and fix it if it is affected.

What it is: CVE-2025-57851 is a medium-severity vulnerability in Red Hat Multicluster Engine for Kubernetes, published on 8 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-57851 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-2025-57851/ (Markdown: https://insights.sbomify.com/CVE-2025-57851/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-57851
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-57851
- OSV: https://osv.dev/vulnerability/CVE-2025-57851

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-57851/
Summaries are generated and may contain mistakes; the official description above is the record.