Please report security vulnerabilities privately, using GitHub's private vulnerability reporting: open the "Security" tab on this repository and click "Report a vulnerability", or go directly to https://github.com/contemper-project/contemper/security/advisories/new. Do not open a public issue for a suspected vulnerability.

If you can't use GitHub's form, open a public issue asking for a private contact channel - please don't include any vulnerability details in it.

• Acknowledgement within 7 days.
• An initial assessment - accepted or declined, and severity - within 14 days.
• A fix or mitigation and coordinated public disclosure, via a GitHub Security Advisory (with a CVE where applicable), within 90 days of the report, earlier once a fix is released.
• If a deadline can't be met, we'll tell you why and give you a new date.

You'll be credited in the advisory unless you'd rather stay anonymous.

Only the latest release is supported. Fixes land there; please upgrade before reporting an issue that may already be fixed.

contemper reads OCI images and host tool output to build VM disk images. Things worth knowing when thinking about attack surface:

• contemper parses untrusted image content (manifests, layer tarballs, config files) but never executes anything from an image - there's no code path that runs a binary or script out of the image being converted.
• contemper shells out to host tools (mkfs.ext4, debugfs, e2fsck, qemu-img, qemu-system-*, ...) with fixed argv arrays; it does not build shell command lines from image content.
• Malformed or malicious image content causing a crash, resource exhaustion, or incorrect output is in scope. Vulnerabilities in the host tools contemper shells out to are out of scope for this repo - please report those upstream.