CVE-2026-29004

EUVD-2026-27043

04.05.2026, 18:16

BusyBox before commit 42202bf contains a heap buffer overflow vulnerability in the DHCPv6 client (udhcpc6) DNS_SERVERS option handler in networking/udhcp/d6_dhcpc.c that allows network-adjacent attackers to trigger memory corruption by sending a crafted DHCPv6 response with a malformed D6_OPT_DNS_SERVERS option. Attackers can exploit incorrect heap buffer allocation calculations in the option_to_env() function to cause denial of service or achieve arbitrary code execution on embedded systems without heap hardening.

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	8.1 HIGH	ADJACENT_NETWORK	LOW	NONE	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Awaiting analysis

This vulnerability is currently awaiting analysis.

Base Score

CVSS 3.x

EPSS Score

Percentile: 1%

Common Weakness Enumeration

CWE-122 - Heap-based Buffer Overflow
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

References

https://busybox.net/

https://github.com/vda-linux/busybox_mirror/commit/42202bfb1e6ac51fa995beda8be4d7b654aeee2a

https://github.com/vda-linux/busybox_mirror/commit/d368f3f7836d1c2484c8f839316e5c93e76d4409

https://www.vulncheck.com/advisories/busybox-dhcpv6-client-heap-buffer-overflow-via-dns-servers

https://y637f9qq2x.com/posts/busybox-dhcpv6-heap-overflow/