Buffer Overflow Vulnerability in DHCP Server by Red Hat
CVE-2026-18103

4.9MEDIUM

Key Information:

Vendor: Red Hat
Status: Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9
Vendor: CVE Published:; 4 August 2026

What is CVE-2026-18103?

A flaw in the DHCP Server allows remote attackers with network access to the OMAPI port to exploit a buffer overflow condition. This occurs when an attacker sends a specially crafted lease creation request with an excessively long InfiniBand MAC address. If the OMAPI port is not properly secured with TSIG key authentication, this vulnerability can result in a persistent denial of service (DoS) where the dhcpd service crashes. Recovery from the crash requires manual intervention, as the service fails to restart automatically.

References

https://access.redhat.com/security/cve/CVE-2026-18103

vdb-entryx_refsource_REDHAT

https://bugzilla.redhat.com/show_bug.cgi?id=2508081

issue-trackingx_refsource_REDHAT

CVSS V3.1

Score:

4.9

Severity:

MEDIUM

Confidentiality:

None

Integrity:

None

Availability:

None

Attack Vector:

Network

Attack Complexity:

Low

Privileges Required:

High

User Interaction:

None

Scope:

Unchanged

Download the Critical Vulnerability Management Cheat Sheet

Timeline

Vulnerability published
Aug 4, 2026
Vulnerability Reserved
Jul 28, 2026

Credit

This issue was discovered by Martin Osvald (Red Hat).

CVE-2026-18103 Data

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