CVE-2025-4374 is a security vulnerability identified in Red Hat Quay 3, a container image registry platform widely used for managing and distributing container images. The flaw arises when an organization is configured to act as a proxy cache. In this mode, if a user or automated robot attempts to pull a container image that has not yet been mirrored locally, the system erroneously grants "Admin" permissions on the newly created repository to that user or robot. This incorrect privilege assignment means that unauthorized users can gain elevated administrative rights over repositories they should not control. The vulnerability has a CVSS 3.1 base score of 6.5, indicating a medium severity level. The vector details (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N) show that the vulnerability is remotely exploitable over the network without requiring authentication or user interaction, and it impacts confidentiality and integrity but not availability. The flaw could allow unauthorized users to modify repository content, potentially injecting malicious images or altering existing ones, thereby compromising the integrity of containerized applications relying on these images. No known exploits are currently reported in the wild, and no patches or fixes have been linked yet. The vulnerability was published on May 6, 2025, and is recognized by Red Hat and CISA as a valid security issue.

For European organizations, this vulnerability poses a significant risk, especially for enterprises and service providers that rely on Red Hat Quay 3 for container image management and distribution. Unauthorized administrative access to repositories can lead to the insertion of malicious container images, which may propagate through development pipelines and production environments, potentially causing data breaches, service disruptions, or supply chain attacks. Confidentiality is impacted as unauthorized users could access sensitive image metadata or configuration. Integrity is at risk due to the possibility of unauthorized modification or replacement of container images. Although availability is not directly affected, the downstream consequences of compromised images could lead to operational disruptions. Organizations in sectors with high container adoption, such as finance, telecommunications, and critical infrastructure, may face increased exposure. Additionally, the ease of exploitation without authentication or user interaction increases the threat level, making automated attacks feasible. The lack of current known exploits provides a window for mitigation, but the medium severity score underscores the need for prompt attention.

To mitigate this vulnerability, European organizations should first verify if they are using Red Hat Quay 3 in proxy cache mode. Immediate steps include restricting access to the Quay instance to trusted networks and users to reduce exposure. Implement strict network segmentation and firewall rules to limit who can interact with the proxy cache functionality. Monitor repository creation events and audit permissions regularly to detect any unauthorized privilege escalations. Employ image signing and verification mechanisms to ensure the integrity of container images before deployment. Organizations should stay alert for official patches or updates from Red Hat and apply them promptly once available. In the interim, consider disabling proxy cache functionality if feasible or implementing additional access controls at the orchestration or CI/CD pipeline level to prevent unauthorized repository creation or modification. Logging and alerting on anomalous repository permission changes can provide early detection of exploitation attempts. Finally, educating DevOps and security teams about this vulnerability will help in recognizing and responding to suspicious activities related to container image repositories.