CVE-2026-55606
Medium
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.
SeverityMedium
CVSS6.5
Exploit probability—
ProductOpenwrt Odhcpd
PublishedOct 23, 2026
First seenOct 23, 2026
Weakness typeCWE-126CWE-126
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| openwrt odhcpd | <= 25.12 | — |
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