CVE-2026-55606
odhcpd: Stack buffer overread via DUID length endianness mismatch in memcmp()
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-126 |
| Vendor | openwrt |
| Product | odhcpd |
| Published | Oct 23, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
Low
Affected Versions
openwrt / odhcpd
<= 25.12
References
github.com: https://github.com/openwrt/odhcpd/security/advisories/GHSA-x8x4-7gvf-gp45 github.com: https://github.com/openwrt/odhcpd/pull/401 github.com: https://github.com/openwrt/odhcpd/commit/6907f28f9ddeef9f69f5ee10bbc9ba8adc0ef57f github.com: https://github.com/openwrt/odhcpd/commit/ed38cffa927d5fd450d20bfd3f7fb8d8e8fff301