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.

Project Subscriptions

Vendors Products
Dhcp-server Subscribe
Dhcp-server Subscribe
Enterprise Linux Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

To mitigate this issue, secure OMAPI access by configuring TSIG key authentication to prevent unauthorized connections to the OMAPI port (7911). If the `dhcpd` service has already crashed due to this flaw, manually remove the problematic InfiniBand lease entry from `/var/lib/dhcpd/dhcpd.leases` and then restart the `dhcpd` service. Restarting the `dhcpd` service may temporarily interrupt DHCP services for clients.

History

Wed, 05 Aug 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 05 Aug 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Low


Wed, 05 Aug 2026 10:45:00 +0000

Type Values Removed Values Added
First Time appeared Dhcp-server
Dhcp-server dhcp-server
Vendors & Products Dhcp-server
Dhcp-server dhcp-server

Tue, 04 Aug 2026 23:30:00 +0000

Type Values Removed Values Added
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.
Title Dhcp-server: dhcp-server: persistent denial of service due to buffer overflow via omapi
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-120
CPEs cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 4.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-08-05T13:58:53.130Z

Reserved: 2026-07-28T17:35:42.520Z

Link: CVE-2026-18103

cve-icon Vulnrichment

Updated: 2026-08-05T13:58:49.665Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Low

Publid Date: 2026-07-28T17:35:55Z

Links: CVE-2026-18103 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-05T10:18:51Z

Weaknesses