runc is a CLI tool for spawning and running containers according to the OCI specification. Versions 1.0.0-rc3 through 1.2.7, 1.3.0-rc.1 through 1.3.2, and 1.4.0-rc.1 through 1.4.0-rc.2, due to insufficient checks when bind-mounting /dev/pts/$n to /dev/console inside the container, an attacker can trick runc into bind-mounting paths which would normally be made read-only or be masked onto a path that the attacker can write to. This attack is very similar in concept and application to CVE-2025-31133, except that it attacks a similar vulnerability in a different target (namely, the bind-mount of /dev/pts/$n to /dev/console as configured for all containers that allocate a console).

This happens after pivot_root(2), so this cannot be used to write to host files directly -- however, as with CVE-2025-31133, this can load to denial of service of the host or a container breakout by providing the attacker with a writable copy of /proc/sysrq-trigger or /proc/sys/kernel/core_pattern (respectively). This issue is fixed in versions 1.2.8, 1.3.3 and 1.4.0-rc.3.