CVE-2026-57231: Podman: Malformed Image can trick podman run into leaking host environment variables into the container
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 5.8.4 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.0.0 - Configuration
Ensure container images do not define environment variables as just a key (no value), and do not use '*' to cause Podman to pass all host variables into the container.
Podman environment variable specification in container image = Do not use an asterisk (*) to pass all host variables; avoid image env entries that contain only a key with no value
Event History
Frequently Asked Questions
What is the severity of CVE-2026-57231?
The severity of CVE-2026-57231 is rated high with a score of 7.5.
How do I fix CVE-2026-57231?
To fix CVE-2026-57231, upgrade Podman to version 5.8.5 or later.
What type of issue is CVE-2026-57231?
CVE-2026-57231 is classified as an information leak vulnerability.
What versions of Podman are affected by CVE-2026-57231?
Podman versions from 1.8.1 to 5.8.4 are affected by CVE-2026-57231.
How does CVE-2026-57231 affect the host environment?
CVE-2026-57231 can lead to the leaking of host environment variables into the container due to malformed images.