CVE-2018-20679: Busybox

High severity, CVSS 7.5. EPSS: 7.7% chance of exploitation in the next 30 days.

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.

Affected products

• Busybox Busybox: before 1.30.0 (fixed in 1.30.0)
• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only; version 18.10 only

Published 2019-01-09. Last modified 2026-06-17.