CVE-2025-57851 is a medium-severity vulnerability affecting RedHat's Advanced Cluster Management for Kubernetes. A container privilege escalation flaw was found, which allows non-root users to potentially gain root privileges inside affected containers. The vulnerability is attributed to the misconfiguration of the /etc/passwd file, which is created with group-writable permissions during the build process. An attacker exploiting this flaw can leverage their membership in the root group to modify the /etc/passwd file and create new users with arbitrary user IDs, including UID 0.
The CVSS score for this vulnerability is 6.4, indicating a medium severity level. This rating is significant as it highlights the potential risks associated with the flaw, particularly in environments where the Advanced Cluster Management for Kubernetes is deployed. Organizations utilizing this software should take the vulnerability seriously, as the implications of a successful exploit can lead to unauthorized access and control over the affected containers.
Organizations should prioritize addressing this vulnerability in their patch management cycles. The flaw was published on April 8, 2026, and has been classified with high confidentiality, integrity, and availability impacts. Given the nature of the vulnerability and its exploitation potential, organizations are advised to review their configurations and ensure they are not leaving their systems exposed.
Remediation should be prioritized as part of an ongoing security strategy, especially for organizations that operate within multi-cluster environments. Immediate patching or updates should be considered to mitigate the risks associated with this vulnerability.
Vulnerability Details
The vulnerability allows an attacker to exploit permissions issues associated with the /etc/passwd file within specific Kubernetes images. The attack vector is local, requiring a user to already have some level of access to the container. The complexity of the attack is rated as high, and it requires a user to have high privileges to execute commands. No user interaction is needed for the exploitation, making it a critical concern for affected organizations.
Technical Analysis
The root cause of this vulnerability stems from the way the /etc/passwd file is created with group-writable permissions during the build process of certain Multicluster Engine for Kubernetes images. Attackers who can execute commands within the affected container can modify the /etc/passwd file due to their membership in the root group. This flaw can lead to various impacts, including high confidentiality, integrity, and availability issues, as attackers may create users with arbitrary user IDs, including UID 0, thereby obtaining full root privileges within the container.
Risk & Impact Analysis
The real-world risk associated with CVE-2025-57851 includes the potential for unauthorized access and control over containerized applications. Organizations that deploy the Advanced Cluster Management for Kubernetes are particularly vulnerable, as the exploit can significantly impact confidentiality, integrity, and availability of their services. The medium CVSS score indicates that while the vulnerability is not the most critical, it poses substantial risks that should not be overlooked. Organizations are urged to assess their exposure and implement necessary mitigations without delay.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected product is RedHat's Advanced Cluster Management for Kubernetes. All versions prior to the vendor patch are vulnerable to this issue. Organizations should consult with RedHat for the latest security patches and updates to mitigate the risk.
Mitigation & Remediation
Organizations should implement patches and updates to remediate this vulnerability. It is essential to verify the permissions of the /etc/passwd file in the affected containers and adjust them accordingly to prevent unauthorized modifications. If a patch is not immediately available, consider applying configuration hardening measures to restrict access to sensitive files. Regular security assessments and penetration testing can also help identify any similar weaknesses in the environment.
Detection Guidance
To detect potential exploitation of this vulnerability, organizations should monitor logs for any unauthorized changes to the /etc/passwd file. Behavioral anomalies within the container environments can also indicate an attempted exploit. Network signatures that alert to abnormal access patterns and system changes should be incorporated into monitoring frameworks to identify potential intrusions.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2025-57851 lies in its representation of broader security concerns within containerized environments. As organizations increasingly adopt Kubernetes and related technologies, vulnerabilities such as this highlight the need for stringent security controls and proactive threat management strategies. Security teams should learn from this incident to improve their defenses, focusing on proper permissions management and regular audits. Implementing a comprehensive security framework will help mitigate similar vulnerabilities in the future.
For a deeper understanding of security practices, organizations can refer to resources on vulnerability management, penetration testing methodology, and security testing best practices to enhance their security posture.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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