crun is an open source OCI Container Runtime fully written in C. In affected versions A malicious container image could trick the krun handler into escaping the root filesystem, allowing file creation or modification on the host. No special permissions are needed, only the ability for the current user to write to the target file. The problem is fixed in crun 1.20 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.