odhcpd: Stack buffer overflow in DHCPv6 IA reply serialization (2 independent sites)
Exact source revision recorded 23 Oct 2026 16:01:20 UTC. It does not establish the source's current position. Latest evidence.
cve-program · CVE-2026-53921
Publishedodhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. Prior to version 25.12, odhcpd's DHCPv6 IA response handler writes past the end of a fixed 512-byte stack buffer (pdbuf) when a single DHCPv6 REQUEST carries enough IA options to nearly exhaust the reply space. Two independent overflow sites exist in the same call chain, both reachable from the network via a single unauthenticated UDP packet. odhcpd runs as root on OpenWrt; embedded targets often lack stack canaries and ASLR, making code execution realistic. This issue has been patched in version 25.12.
- Source published
- 23 Oct 2026 13:20:30 UTC
- Source modified
- 23 Oct 2026 13:20:30 UTC
- Observed here
- 23 Oct 2026 16:01:20 UTC
- Source terms
- CVE Program Terms of Use
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CVSS 3.1 · 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H