CVE-2026-55606
odhcpd: Stack buffer overread via DUID length endianness mismatch in memcmp()
- State
- Published
- Severity
- 6.5 Medium
- Published
- Oct 23, 2026
- Updated
- Oct 29, 2026
- Reserved
- Jun 16, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.5 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L | GitHub_M |
Weaknesses
- CWE-126 Buffer Over-read
Affected Products
| Product | Versions |
|---|---|
odhcpdopenwrt |
|
References
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