CVE-2026-55606

Impact

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.

Affected packages

This record carries no package version data, so it cannot be matched against a dependency list automatically. Read the advisory and compare your version by hand.

Weakness classification

References

• NVD record
• CVE.org record
• https://github.com/openwrt/odhcpd/commit/6907f28f9ddeef9f69f5ee10bbc9ba8adc0ef57f
• https://github.com/openwrt/odhcpd/commit/ed38cffa927d5fd450d20bfd3f7fb8d8e8fff301
• https://github.com/openwrt/odhcpd/pull/401
• https://github.com/openwrt/odhcpd/security/advisories/GHSA-x8x4-7gvf-gp45