CVE-2026-57231 in podman
Summary
by MITRE • 06/26/2026
Podman is a tool for managing OCI containers and pods. From 1.8.1 until 5.8.4, a container image that contains a environment variable with just a key and no value can trick podman into passing that variable from the host into the container. This is made worse by the fact that using an asterisk (*) will cause podman to pass all host variables into the container. So essentially a malicious image can exfiltrate all podman environment variables that are set in the session from where the container is launched. This vulnerability is fixed in 5.8.4 and 6.0.0.
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Analysis
by VulDB Data Team • 06/26/2026
This vulnerability represents a critical environment variable injection flaw in Podman that allows malicious container images to extract sensitive host environment information. The issue stems from how Podman processes environment variables when launching containers, specifically handling cases where environment variables are defined with only a key and no explicit value. When such variables are present in a container image, the container runtime incorrectly passes these host-level environment variables into the container context without proper sanitization or validation.
The technical exploitation occurs through a combination of two factors that amplify the security impact significantly. First, Podman's handling of environment variables with empty values creates an unintended path where host environment variables can be inadvertently exposed to containers. Second, the asterisk wildcard functionality in Podman's environment variable processing further compounds this vulnerability by allowing complete host environment leakage when specific patterns are matched. This dual mechanism creates a scenario where a malicious image can programmatically extract all environment variables from the host system that were set during the session where podman was executed.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides adversaries with access to potentially sensitive configuration data, authentication tokens, and system-specific environment settings that could be leveraged for further attacks. The vulnerability affects all Podman versions between 1.8.1 and 5.8.3, representing a substantial attack surface where any container execution could potentially lead to unauthorized environment variable exposure. This represents a violation of the principle of least privilege in container security, as the container runtime fails to properly isolate host and container environments during the variable propagation process.
Security practitioners should note this vulnerability aligns with CWE-254, which addresses weaknesses in protection mechanisms and improper handling of sensitive data, and maps to ATT&CK technique T1552.001 for credentials in files and T1552.006 for .bashrc and .profile. The fix implemented in versions 5.8.4 and 6.0.0 addresses the core parsing logic of environment variables, ensuring that host environment variables are properly isolated from container execution contexts and that wildcard matching no longer results in complete environment leakage.
Organizations using Podman should immediately upgrade to version 5.8.4 or later, or to version 6.0.0 if available, as this vulnerability represents a significant risk to containerized environments where sensitive information might be exposed through environment variable injection. The remediation process should include auditing existing container images for potential exploitation vectors and implementing proper environment variable sanitization practices to prevent similar issues in other container runtimes or deployment tools that might exhibit similar behaviors. Additionally, system administrators should review their current Podman configurations and ensure that environment variable handling follows secure defaults that prevent unintended host-to-container information flow.
This vulnerability highlights the importance of rigorous input validation and environment isolation in container orchestration tools, particularly when dealing with user-supplied images that may contain malicious payloads designed to exploit runtime implementation flaws. The security implications extend beyond simple information disclosure to include potential credential compromise and system reconnaissance capabilities that could be leveraged for privilege escalation or lateral movement attacks within containerized environments.