CVE-2026-57231

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.

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.

Summary

An 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.

Details

podman run allows --env VAR1 or --env VAR* which will read the variable values from the current environment and then passes them into the container. However because the same parsing logic was reused for the image config env section that means that an image variable could also gain access to that.

Patch

That image spec requires the env variables to be in the form of key=value, so to address this invalid formatted variables get rejected and the container will not run.

Fixed in https://github.com/podman-container-tools/podman/commit/6c431b73dbf8e4b20b778644d7a80caebdb75050

Workaround

Do not run untrusted images. Before running an image consider inspecting the config with podman image inspect --format '{{.Config.Env}}' <image> and check for any variables that do not have a value assigned.

The podman tool manages pods, container images, and containers. It is part of the libpod library, which is for applications that use container pods. Container pods is a concept in Kubernetes.

Security Fix(es):

• golang.org/x/crypto/ssh: golang: golang.org/x/crypto/ssh: Denial of Service via crafted SSH certificate (CVE-2026-39835)

• golang.org/x/crypto/ssh: golang.org/x/crypto/ssh: Denial of Service via crafted public key with excessive parameters (CVE-2026-39829)

• golang.org/x/crypto/ssh: golang.org/x/crypto/ssh: Denial of Service via resource leak from unsolicited SSH responses (CVE-2026-39830)

• golang.org/x/crypto/ssh/agent: golang.org/x/crypto/ssh/agent: Security bypass due to improper handling of key restrictions (CVE-2026-39832)

• golang.org/x/crypto/ssh/knownhosts: golang: golang.org/x/crypto/ssh/knownhosts: Revocation bypass via unchecked SignatureKey (CVE-2026-42508)

• golang.org/x/net/html: golang: golang.org/x/net/html: Cross-Site Scripting via HTML parsing bypass (CVE-2026-27136)

• golang.org/x/net/html: golang.org/x/net/html: Arbitrary code execution via Cross-Site Scripting (CVE-2026-25681)

• podman: Podman: Information disclosure via malicious container image environment variables (CVE-2026-57231)

Bug Fix(es) and Enhancement(s):

• podman does not clean up all files and leaves orphaned files consuming disk space [rhel-10.2.z] (JIRA:Rocky Linux-173842)

• [FJ10.2 Bug]: [REG]The "podman-remote save" command fails for rootless users. [rhel-10.2.z] (JIRA:Rocky Linux-192440)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The podman tool manages pods, container images, and containers. It is part of the libpod library, which is for applications that use container pods. Container pods is a concept in Kubernetes.

Security Fix(es):

• golang.org/x/crypto/ssh: golang: golang.org/x/crypto/ssh: Denial of Service via crafted SSH certificate (CVE-2026-39835)

• golang.org/x/crypto/ssh: golang.org/x/crypto/ssh: Denial of Service via crafted public key with excessive parameters (CVE-2026-39829)

• golang.org/x/crypto/ssh/agent: golang.org/x/crypto/ssh/agent: Security bypass due to improper handling of key restrictions (CVE-2026-39832)

• golang.org/x/crypto/ssh/knownhosts: golang: golang.org/x/crypto/ssh/knownhosts: Revocation bypass via unchecked SignatureKey (CVE-2026-42508)

• golang.org/x/net/html: golang: golang.org/x/net/html: Cross-Site Scripting via HTML parsing bypass (CVE-2026-27136)

• golang.org/x/net/html: golang.org/x/net/html: Arbitrary code execution via Cross-Site Scripting (CVE-2026-25681)

• podman: Podman: Information disclosure via malicious container image environment variables (CVE-2026-57231)

Bug Fix(es) and Enhancement(s):

• podman does not clean up all files and leaves orphaned files consuming disk space [rhel-9.8.z] (JIRA:Rocky Linux-173988)

• [FJ9.8 Bug]: [REG]The "podman-remote save" command fails for rootless users. [rhel-9.8.z] (JIRA:Rocky Linux-192439)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The container-tools module contains tools for working with containers, notably podman, buildah, skopeo, and runc.

Security Fix(es):

• net: golang: Go net package: Denial of Service via long CNAME response in LookupCNAME (CVE-2026-33811)

• golang.org/x/crypto/ssh: golang: golang.org/x/crypto/ssh: Denial of Service via crafted SSH certificate (CVE-2026-39835)

• podman: Podman: Information disclosure via malicious container image environment variables (CVE-2026-57231)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

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.

The podman tool manages pods, container images, and containers. It is part of the libpod library, which is for applications that use container pods. Container pods is a concept in Kubernetes.

Security Fix(es):

• golang.org/x/crypto/ssh: golang: golang.org/x/crypto/ssh: Denial of Service via crafted SSH certificate (CVE-2026-39835)
• golang.org/x/crypto/ssh: golang.org/x/crypto/ssh: Denial of Service via crafted public key with excessive parameters (CVE-2026-39829)
• golang.org/x/crypto/ssh/agent: golang.org/x/crypto/ssh/agent: Security bypass due to improper handling of key restrictions (CVE-2026-39832)
• golang.org/x/crypto/ssh/knownhosts: golang: golang.org/x/crypto/ssh/knownhosts: Revocation bypass via unchecked SignatureKey (CVE-2026-42508)
• golang.org/x/net/html: golang: golang.org/x/net/html: Cross-Site Scripting via HTML parsing bypass (CVE-2026-27136)
• golang.org/x/net/html: golang.org/x/net/html: Arbitrary code execution via Cross-Site Scripting (CVE-2026-25681)
• podman: Podman: Information disclosure via malicious container image environment variables (CVE-2026-57231)

Bug Fix(es) and Enhancement(s):

• podman does not clean up all files and leaves orphaned files consuming disk space [almalinux-9.8.z] (JIRA:AlmaLinux-173988)
• [FJ9.8 Bug]: [REG]The "podman-remote save" command fails for rootless users. [almalinux-9.8.z] (JIRA:AlmaLinux-192439)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The container-tools module contains tools for working with containers, notably podman, buildah, skopeo, and runc.

Security Fix(es):

• net: golang: Go net package: Denial of Service via long CNAME response in LookupCNAME (CVE-2026-33811)
• golang.org/x/crypto/ssh: golang: golang.org/x/crypto/ssh: Denial of Service via crafted SSH certificate (CVE-2026-39835)
• podman: Podman: Information disclosure via malicious container image environment variables (CVE-2026-57231)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

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.

• CVE-2026-57231: reject image environment variables that are not strict key=value in ParseImageEnvs(), preventing a crafted image from leaking matching host environment variables into the container

Podman: Malformed Image can trick podman run into leaking host environment variables into the container in github.com/containers/libpod

These are all security issues fixed in the podman-6.0.2-1.1 package on the GA media of openSUSE Tumbleweed.

This update for podman fixes the following issues:

Security issues fixed:

• CVE-2026-55686: Podman: WORKDIR symlink traversal vulnerability (bsc#1268579).
• CVE-2026-57231: specially crafted image can trick podman run into leaking host environment variables into the container (bsc#1269471).

Non security issue fixed:

• catatonit missing in /usr/libexec/podman/ (bsc#1248988).

This update for podman fixes the following issues:

• CVE-2026-55686: Podman: WORKDIR symlink traversal vulnerability (bsc#1268579).
• CVE-2026-57231: specially crafted image can trick podman run into leaking host environment variables into the container (bsc#1269471).

This update for podman fixes the following issues:

Security issues fixed:

• CVE-2026-55686: Podman: WORKDIR symlink traversal vulnerability (bsc#1268579).
• CVE-2026-57231: specially crafted image can trick podman run into leaking host environment variables into the container (bsc#1269471).

Non security issue fixed:

• catatonit missing in /usr/libexec/podman/ (bsc#1248988).

This update for podman fixes the following issues:

• CVE-2026-55686: Podman: WORKDIR symlink traversal vulnerability (bsc#1268579).
• CVE-2026-57231: specially crafted image can trick podman run into leaking host environment variables into the container (bsc#1269471).

This update for podman fixes the following issues:

• CVE-2026-55686: specially crafted image where the WORKDIR path contains a symlink allows for directory creation and ownership modification on the host filesystem (bsc#1268579).
• CVE-2026-57231: specially crafted image can trick podman run into leaking host environment variables into the container (bsc#1269471).

This update for podman fixes the following issues:

• CVE-2026-55686: specially crafted image where the WORKDIR path contains a symlink allows for directory creation and ownership modification on the host filesystem (bsc#1268579).
• CVE-2026-57231: specially crafted image can trick podman run into leaking host environment variables into the container (bsc#1269471).

This update for podman fixes the following issues:

• CVE-2026-55686: specially crafted image where the WORKDIR path contains a symlink allows for directory creation and ownership modification on the host filesystem (bsc#1268579).
• CVE-2026-57231: specially crafted image can trick podman run into leaking host environment variables into the container (bsc#1269471).