odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In versions 25.12 and prior, odhcpd's DHCPv6 self-loop detection at dhcpv6.c:720 uses a network-byte-order DUID length value directly as the memcmp() size parameter. On little-endian hosts, this causes memcmp() to read far beyond the stack buffer — a single unauthenticated DHCPv6 packet triggers a 2560-byte overread from a 128-byte buffer. At time of publication, there are no publicly available patches.
History

Fri, 23 Oct 2026 23:45:00 +0000

Type Values Removed Values Added
First Time appeared Openwrt
Openwrt odhcpd
Vendors & Products Openwrt
Openwrt odhcpd

Fri, 23 Oct 2026 13:30:00 +0000

Type Values Removed Values Added
Description odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In versions 25.12 and prior, odhcpd's DHCPv6 self-loop detection at dhcpv6.c:720 uses a network-byte-order DUID length value directly as the memcmp() size parameter. On little-endian hosts, this causes memcmp() to read far beyond the stack buffer — a single unauthenticated DHCPv6 packet triggers a 2560-byte overread from a 128-byte buffer. At time of publication, there are no publicly available patches.
Title odhcpd: Stack buffer overread via DUID length endianness mismatch in memcmp()
Weaknesses CWE-126
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-10-23T13:21:21.038Z

Updated: 2026-10-23T13:21:21.038Z

Reserved: 2026-06-16T23:31:22.445Z

Link: CVE-2026-55606

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-23T14:17:53.850

Modified: 2026-10-23T19:37:11.060

Link: CVE-2026-55606

cve-icon Redhat

No data.