CVE-2026-18103
Publication date 13 August 2026
Last updated 18 August 2026
Ubuntu priority
Description
A flaw was found in dhcp-server. A remote attacker with network access to the OMAPI (Open Management Application Programming Interface) port, especially if not secured with TSIG (Transaction Signature) key authentication, could send a specially crafted lease creation request. This request, containing an overly long InfiniBand MAC address, triggers a buffer overflow in the `print_hw_addr()` function. Successful exploitation leads to a persistent denial of service (DoS), causing the `dhcpd` service to crash and preventing it from restarting without manual intervention.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| isc-dhcp | 26.04 LTS resolute |
Vulnerable, fix deferred
|
| 24.04 LTS noble |
Vulnerable, fix deferred
|
|
| 22.04 LTS jammy |
Vulnerable, fix deferred
|
|
| 20.04 LTS focal |
Vulnerable, fix deferred
|
|
| 18.04 LTS bionic |
Vulnerable, fix deferred
|
|
| 16.04 LTS xenial |
Vulnerable, fix deferred
|
|
| 14.04 LTS trusty |
Vulnerable, fix deferred
|
Notes
mdeslaur
There are no details about a fix for this issue from isc-dhcp developers as of 2026-08-17. The only info available is in the Red Hat bug.
Severity score breakdown
CVSS version: CVSS v3.0
Base score
4.9 · Medium
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H