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OpenAdvisories
Medium · 4.9 CVE-2026-18103 EUVD-2026-52999GHSA-wq4j-5vp3-jcrx

Dhcp-server: dhcp-server: persistent denial of service due to buffer overflow via omapi

Published Aug 4, 2026 · Updated Nov 10, 2026 · Assigned by redhat

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.

Affected products

VendorProductAffectedFixed
Red Hat Red Hat Enterprise Linux 9 — —
Red Hat Red Hat Enterprise Linux 6 — —
Red Hat Red Hat Enterprise Linux 7 — —
Red Hat Red Hat Enterprise Linux 8 — —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 13 isc-dhcp No fix yet —
Debian 12 isc-dhcp No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.04 LTS isc-dhcp No fix yet —
Ubuntu 24.04 LTS isc-dhcp No fix yet —
Ubuntu 22.04 LTS isc-dhcp No fix yet —
Ubuntu 20.04 LTS isc-dhcp No fix yet —
Ubuntu 18.04 LTS isc-dhcp No fix yet —
Show 2 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 16.04 LTS isc-dhcp No fix yet —
Ubuntu Pro 14.04 LTS isc-dhcp No fix yet —

Rocky Linux

Errata ↗
ReleasePackageFixed inAdvisory
Rocky Linux 9 dhcp-relay +3 2:4.4.2-22.b1.el9.rocky.0.1 RLSA-2026:97486

Advisories 2

References