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.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
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
Which versions are affected by CVE-2025-57851?
It affects 1 product.
Products include 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 Open Cluster Management (OCM): Cross-cluster privilege escalation via improper Kubernetes client certificate renewal validation
- CVE-2023-3027 Privilege escalation in RHACM
- CVE-2022-3841 Server-side request forgery in RHACM
- CVE-2026-71474 Insights-client-rhel9: insights-client: pull-secret bearer token written to logs on non-200 ccx response
- CVE-2026-71475 Insights-client-rhel9: insights-client: spoke-controlled clusterid injected unencoded into insights api url path
Sources
Also known as GHSA-87qg-cwpg-cjvw.