lxc vulnerabilities

UBUNTU-CVE-2026-100395

[lxc-copy host-context hostname update follows symlink]

lxc lxc-user-nic insufficient ownership validation allows cross-tenant OVS port deletion

lxc is a Linux container runtime. In the setuid helper lxc-user-nic, the delete path contains a logic flaw in the find_line() function that allows an unprivileged user to delete OVS-attached network interfaces belonging to other users. When lxc-user-nic delete scans its NIC database to authorize a deletion request, the interface name comparison can set the authorization flag based on a name match alone, even when the ownership, type, and link fields in that database entry belong to a different user. The vulnerable check sits after the goto next label handling, meaning it is reachable on lines where earlier ownership checks failed or were skip

• Update to 1:5.0.2-1+deb12u4

CVE-2022-47952

lxc-user-nic in lxc through 5.0.1 is installed setuid root, and may allow local users to infer whether any file exists, even within a protected directory tree, because "Failed to open" often indicates that a file does not exist, whereas "does not refer to a network namespace path" often indicates that a file exists. NOTE: this is different from CVE-2018-6556 because the CVE-2018-6556 fix design was based on the premise that "we will report back to the user that the open() failed but the user has no way of knowing why it failed"; however, in many realistic cases, there are no plausible reasons for failing except that the file does not exist.

• Update to 1:5.0.2-1

CVE-2017-18641

In LXC 2.0, many template scripts download code over cleartext HTTP, and omit a digital-signature check, before running it to bootstrap containers.

• Update to 1:3.0.3-1

CVE-2019-5736

runc through 1.0-rc6, as used in Docker before 18.09.2 and other products, allows attackers to overwrite the host runc binary (and consequently obtain host root access) by leveraging the ability to execute a command as root within one of these types of containers: (1) a new container with an attacker-controlled image, or (2) an existing container, to which the attacker previously had write access, that can be attached with docker exec. This occurs because of file-descriptor mishandling, related to /proc/self/exe.

• Update to 1:3.1.0+really3.0.3-4

The lxc-user-nic component of LXC allows unprivileged users to open arbitrary files

lxc-user-nic when asked to delete a network interface will unconditionally open a user provided path. This code path may be used by an unprivileged user to check for the existence of a path which they wouldn't otherwise be able to reach. It may also be used to trigger side effects by causing a (read-only) open of special kernel files (ptmx, proc, sys). Affected releases are LXC: 2.0 versions above and including 2.0.9; 3.0 versions above and including 3.0.0, prior to 3.0.2.

• Update to 1:2.0.9-6.1

CVE-2016-8649

lxc-attach in LXC before 1.0.9 and 2.x before 2.0.6 allows an attacker inside of an unprivileged container to use an inherited file descriptor, of the host's /proc, to access the rest of the host's filesystem via the openat() family of syscalls.

• Update to 1:2.0.6-1

CVE-2017-5985

lxc-user-nic in Linux Containers (LXC) allows local users with a lxc-usernet allocation to create network interfaces on the host and choose the name of those interfaces by leveraging lack of netns ownership check.

• Update to 1:2.0.7-2

CVE-2016-10124

An issue was discovered in Linux Containers (LXC) before 2016-02-22. When executing a program via lxc-attach, the nonpriv session can escape to the parent session by using the TIOCSTI ioctl to push characters into the terminal's input buffer, allowing an attacker to escape the container.

• Update to 1:2.0.0-1

CVE-2015-1335

lxc-start in lxc before 1.0.8 and 1.1.x before 1.1.4 allows local container administrators to escape AppArmor confinement via a symlink attack on a (1) mount target or (2) bind mount source.

• Update to 1:1.0.8-1

CVE-2015-1334

attach.c in LXC 1.1.2 and earlier uses the proc filesystem in a container, which allows local container users to escape AppArmor or SELinux confinement by mounting a proc filesystem with a crafted (1) AppArmor profile or (2) SELinux label.

• Update to 1:1.0.7-4

CVE-2015-1331

lxclock.c in LXC 1.1.2 and earlier allows local users to create arbitrary files via a symlink attack on /run/lock/lxc/*.

• Update to 1:1.0.7-4

CVE-2013-6441

The lxc-sshd template (templates/lxc-sshd.in) in LXC before 1.0.0.beta2 uses read-write permissions when mounting /sbin/init, which allows local users to gain privileges by modifying the init file.

• Update to 1.0.0-1