CVE-2025-4953 is a vulnerability identified in Podman, specifically impacting the Red Hat OpenShift Container Platform 4.12. The flaw arises during the podman build process when using the RUN --mount=type=bind directive. Normally, data written to these bind mounts during the build should be discarded after the build completes to avoid leaving residual files on the host system. However, due to this vulnerability, files created inside the container during the build persist in the temporary build context directory on the host. These files are created with insecure permissions, making them accessible to unauthorized users on the host system. This exposure can lead to leakage of sensitive build artifacts or confidential data that was intended to remain isolated within the container environment. The vulnerability does not require any privileges or user interaction to exploit, and it can be triggered remotely if an attacker can initiate container builds. The CVSS 3.1 base score of 7.4 reflects a high severity, primarily due to the impact on confidentiality and integrity, although availability is unaffected. No public exploits have been reported yet, but the risk remains significant given the widespread use of Podman and OpenShift in enterprise container orchestration. The issue underscores the importance of secure handling of temporary files and build contexts in containerized workflows to prevent data leakage from ephemeral build environments.

The vulnerability can lead to unauthorized disclosure of sensitive data generated during container builds, including secrets, credentials, or proprietary code fragments that may be written to temporary files. This exposure compromises confidentiality and integrity by allowing attackers or unauthorized users on the host to access or tamper with these files. Organizations relying on container builds for continuous integration and deployment pipelines may face increased risk of intellectual property theft, compliance violations, and potential lateral movement within their infrastructure. Since the vulnerability affects the build context on the host, it could also facilitate further attacks by providing attackers with information about the build environment or application internals. Although availability is not directly impacted, the breach of confidentiality and integrity can have severe operational and reputational consequences. Enterprises using Red Hat OpenShift Container Platform 4.12 and Podman in production environments are particularly vulnerable, especially if build environments are shared or insufficiently isolated. The lack of required authentication or user interaction lowers the barrier for exploitation, increasing the threat surface for automated or remote attacks.

1. Apply vendor patches or updates as soon as they become available from Red Hat or Podman maintainers to address the root cause of the vulnerability. 2. Restrict permissions on temporary build context directories on the host to limit access only to trusted users and processes. 3. Isolate container build environments by using dedicated build hosts or virtual machines to prevent unauthorized access to build artifacts. 4. Implement strict access controls and monitoring on host filesystem locations used during container builds to detect anomalous file creation or access. 5. Avoid writing sensitive data to RUN --mount=type=bind mounts during builds; instead, use secure secrets management solutions integrated with container build pipelines. 6. Regularly audit container build processes and temporary directories for residual files and remove any unauthorized or leftover artifacts promptly. 7. Educate development and DevOps teams about secure container build practices and the risks of exposing build context files. 8. Consider using ephemeral or in-memory filesystems for build contexts where feasible to minimize persistent file exposure. These measures collectively reduce the risk of data leakage and unauthorized access stemming from this vulnerability.