Privilege Escalation via GroupWritable /etc/passwd in MCE for K8s
CVE-2025-57851 Published on April 8, 2026
Mce: privilege escalation via excessive /etc/passwd permissions
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.
Vulnerability Analysis
CVE-2025-57851 can be exploited with local system access, and requires user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Timeline
Reported to Red Hat.
Made public. 225 days later.
Weakness Type
Incorrect Default Permissions
During installation, installed file permissions are set to allow anyone to modify those files.
Products Associated with CVE-2025-57851
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