CVE-2025-57851
MediumCVSS 6.4Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
In Multicluster Engine for Kubernetes images, the /etc/passwd file is created with group-writable permissions. An attacker with container access, even as non-root, who is a member of the root group can modify this file and add a user with any UID, including 0, gaining full root privileges in the container.
Risk Assessment
Privilege escalation in the container may allow an attacker full control over the container and potentially further attacks on the cluster.
Recommendation
Update Multicluster Engine for Kubernetes images to a version where the /etc/passwd permissions are fixed.
Other vulnerabilities in Multicluster Engine for Kubernetes
See all- CVE-2026-66794Critical
In the cluster-proxy-addon component of Multicluster Engine for Kubernetes, an unauthenticated attacker with access to the user-facing route can bypass authentication and authorization checks. By manipulating URL path segments, the attacker can proxy requests to arbitrary services across any managed cluster.
- CVE-2026-10059Critical
A flaw was found in the Multicluster Engine for Kubernetes ClusterCurator controller. A tenant administrator with namespace-scoped privileges can exploit this vulnerability by creating a namespaced ClusterCurator. This action inadvertently grants the tenant administrator the ability to mint a token for a ServiceAccount with cluster-wide administrative authority. This leads to a privilege escalation, allowing the tenant administrator to gain full control over the cluster.
Original NVD description (English source)
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.