A flaw was found in crun. After pivotroot or chroot, crun reopens /dev/null for stdio without preventing symlink follows. If /dev is not mounted and a malicious image replaces /dev/null with a symlink, crun can open a host bind-mounted file and a non-root container process can write to it and chown it. Affected versions are crun 1.29.1 and earlier. This is a separate issue from CVE-2026-47766 and from the /dev/console symlink flaw. No fixed release is published yet.
crun is an open source OCI Container Runtime fully written in C. Prior to version 1.28, crun's default device setup opens the container rootfs /dev directory without ONOFOLLOW. If an OCI bundle contains rootfs/dev as a symlink and the bundle configuration does not mount /dev, crun follows that symlink and creates the default device nodes and stdio symlinks at the symlink target outside the container rootfs. In a local rootful crun replay, this created fixed device nodes and symlinks outside the rootfs before crun returned failure. A pre-existing file named ptmx in the target directory was also replaced by crun's forced ptmx -> pts/ptmx symlink. Version 1.28 fixes the issue.
A flaw was found in crun. During terminal setup, when the OCI configuration does not mount /dev, crun unlinks and recreates /dev/console without preventing symlink follows. A malicious image can make /dev/console a symlink so that crun creates a root-owned file outside the container rootfs. Affected versions are crun 1.29.1 and earlier. This is not CVE-2026-47766, which addressed following a rootfs /dev directory symlink and was fixed in crun 1.28. No fixed release is published yet.
crun is an open source OCI Container Runtime fully written in C. In versions 1.19 through 1.26, the crun exec option -u (--user) is incorrectly parsed. The value 1 is interpreted as UID 0 and GID 0 when it should have been UID 1 and GID 0. The process thus runs with higher privileges than expected. Version 1.27 patches the issue.
crun is an open source OCI Container Runtime fully written in C. In versions 1.19 through 1.26, the crun exec option -u (--user) is incorrectly parsed. The value 1 is interpreted as UID 0 and GID 0 when it should have been UID 1 and GID 0. The process thus runs with higher privileges than expected. Version 1.27 patches the issue.