odhcpd: Stack buffer overflow in DHCPv6 IA reply serialization (2 independent sites)
- Published
- Last modified
- Status
- published
- Known exploitation
- Not listed in CISA KEV
- Fix
- Fixed in 25.12
- Public exploit
- None on Exploit-DB
Summary
odhcpd, the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt, is affected. A single unauthenticated network packet can overflow a stack buffer in its DHCPv6 handling, which could let an attacker run code as root on the device.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
odhcpd 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.
Affected versions
- openwrt odhcpd
fixed in 25.12