CVE-2026-29004: BusyBox DHCPv6 Client Heap Buffer Overflow via DNS_SERVERS
BusyBox before commit 42202bf contains a heap buffer overflow vulnerability in the DHCPv6 client (udhcpc6) DNSSERVERS option handler in networking/udhcp/d6dhcpc.c that allows network-adjacent attackers to trigger memory corruption by sending a crafted DHCPv6 response with a malformed D6OPTDNSSERVERS option. Attackers can exploit incorrect heap buffer allocation calculations in the optiontoenv() function to cause denial of service or achieve arbitrary code execution on embedded systems without heap hardening.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
BusyBox udhcpc6 DHCPv6 client (DNS_SERVERS option handler)to a version that resolves this vulnerability.Patch commit 42202bf
Event History
Frequently Asked Questions
What is the severity of CVE-2026-29004?
CVE-2026-29004 has a high severity due to the potential for memory corruption and remote exploitation.
How do I fix CVE-2026-29004?
To mitigate CVE-2026-29004, update BusyBox to a version after commit 42202bf.
Who is affected by CVE-2026-29004?
CVE-2026-29004 affects users and systems running vulnerable versions of BusyBox with the udhcpc6 DHCPv6 client.
What type of vulnerability is CVE-2026-29004?
CVE-2026-29004 is classified as a heap buffer overflow vulnerability.
Can attackers exploit CVE-2026-29004 remotely?
Yes, attackers can exploit CVE-2026-29004 remotely by sending specially crafted packets to the affected DHCPv6 client.