Vulnerabilidades de runc-app

runc: Malicious image with /dev symlink can trigger limited host filesystem integrity violations

runc is a CLI tool for spawning and running containers according to the OCI specification. In versions prior to 1.3.6, 1.4.0-rc.1, 1.4.0-rc.12, 1.5.0-rc.1, and 1.5.0-rc.1, when setting up the container rootfs, setupPtmx and setupDevSymlinks call os.Remove and os.Symlink with a filepath.Join string which allow an image with /dev as a symlink to trick runc into deleting files called ptmx on the host or creating a hardcoded set of symlinks with specific names and targets in an arbitrary pre-existing host directory. This issue is not exploitable under Docker, because Docker creates a top-level read-only layer that masks any malicious /dev symlink

runc-app, runc-stable regression

USN-7851-1 fixed vulnerabilities in runC. The introduction of a new upstream release has caused regressions in runc-app and runc-stable. This update fixes the problem. Original advisory details: Lei Wang and Li Fubang discovered that runC incorrectly handled masked paths. An attacker could possibly replace a container's /dev/null with a symlink to some other procfs file and possibly escape a container. (CVE-2025-31133) Lei Wang and Li Fubang discovered that runC incorrectly handled the /dev/console bind-mounts. An attacker could potentially exploit this issue to build-mount a symlink and escape a container. (CVE-2025-52565) Li Fub

• Actualiza a 1.3.3-0ubuntu1~25.10.3

runc: LSM labels can be bypassed with malicious config using dummy procfs files

runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7, 1.3.2 and 1.4.0-rc.2, an attacker can trick runc into misdirecting writes to /proc to other procfs files through the use of a racing container with shared mounts (we have also verified this attack is possible to exploit using a standard Dockerfile with docker buildx build as that also permits triggering parallel execution of containers with custom shared mounts configured). This redirect could be through symbolic links in a tmpfs or theoretically other methods such as regular bind-mounts. While similar, the mitigation applied for the

• Actualiza a 1.3.3-0ubuntu1~25.10.2

container escape due to /dev/console mount and related races

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

• Actualiza a 1.3.3-0ubuntu1~25.10.2

runc container escape via "masked path" abuse due to mount race conditions

runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7 and below, 1.3.0-rc.1 through 1.3.1, 1.4.0-rc.1 and 1.4.0-rc.2 files, runc would not perform sufficient verification that the source of the bind-mount (i.e., the container's /dev/null) was actually a real /dev/null inode when using the container's /dev/null to mask. This exposes two methods of attack: an arbitrary mount gadget, leading to host information disclosure, host denial of service, container escape, or a bypassing of maskedPaths. This issue is fixed in versions 1.2.8, 1.3.3 and 1.4.0-rc.3.

• Actualiza a 1.3.3-0ubuntu1~25.10.2