Executive brief
The DHCP server is a critical network service that assigns IP addresses to devices. This flaw allows a remote attacker with access to the management port to crash the DHCP service through a specially crafted request, preventing new devices from connecting to the network until an administrator manually restarts the service. The risk is highest for installations where the management port is not properly restricted or authenticated.
Technical details
A buffer overflow vulnerability exists in the dhcp-server's OMAPI (Open Management Application Programming Interface) handler, specifically in the print_hw_addr() function when processing an overly long InfiniBand MAC address during lease creation. The vulnerability is triggered via network access to the OMAPI port (7911) and requires high privileges (TSIG key authentication must be disabled or bypassed) but no user interaction. Successful exploitation causes the dhcpd service to crash and prevents automatic restart, resulting in persistent denial of service. The vulnerability is classified as CWE-120 (classic buffer overflow) with no remote code execution impact.
Affected products
- ISC dhcp-server <UNKNOWN>
Timeline
- 2026-08-05: disclosed
- 2026-08-05: advisory