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Vulnerability · Published Aug 4, 2026 · Assigned by redhat

CVE-2026-18103Dhcp-server: dhcp-server: persistent denial of service due to buffer overflow via omapi

Medium 4.9

In plain English

A medium-severity buffer overflow in Red Hat Enterprise Linux 6 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 54% of all known vulnerabilities).

Severity (CVSS 3.1)4.9Medium
Exploit odds (30 days)0.7%top 46.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12isc-dhcpno fix listedDEBIAN-CVE-2026-18103
Debian:13isc-dhcpno fix listedDEBIAN-CVE-2026-18103
Ubuntu:22.04:LTSisc-dhcpno fix listedUBUNTU-CVE-2026-18103
Ubuntu:24.04:LTSisc-dhcpno fix listedUBUNTU-CVE-2026-18103
Ubuntu:26.04:LTSisc-dhcpno fix listedUBUNTU-CVE-2026-18103

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat Enterprise Linux 6 see references
Red Hat Red Hat Enterprise Linux 7 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 9 see references

Weakness: CWE-120 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

References