CVE-2026-29004

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.

CVSS 4.0

7.2CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

8.1CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

EPSS

0.4% chance of exploitation in the next 30 days; higher than 31% of CVEs (scores of 2026-10-26)

CWEs

CWE-122, CWE-131

Published

2026-05-04

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

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/

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