CVE-2026-18103

NameCVE-2026-18103
DescriptionA 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
isc-dhcp (PTS)bullseye4.4.1-2.3+deb11u2vulnerable
bullseye (security)4.4.1-2.3+deb11u1vulnerable
bookworm4.4.3-P1-2vulnerable
trixie4.4.3-P1-8vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
isc-dhcpsource(unstable)(unfixed)

Notes

[trixie] - isc-dhcp <ignored> (ISC DHCP not covered by security support in Trixie)
https://bugzilla.redhat.com/show_bug.cgi?id=2508081

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