CVE-2019-6470: ISC Dhcpd

High severity, CVSS 7.5. EPSS: 8.8% chance of exploitation in the next 30 days.

There had existed in one of the ISC BIND libraries a bug in a function that was used by dhcpd when operating in DHCPv6 mode. There was also a bug in dhcpd relating to the use of this function per its documentation, but the bug in the library function prevented this from causing any harm. All releases of dhcpd from ISC contain copies of this, and other, BIND libraries in combinations that have been tested prior to release and are known to not present issues like this. Some third-party packagers of ISC software have modified the dhcpd source, BIND source, or version matchup in ways that create the crash potential. Based on reports available to ISC, the crash probability is large and no analysis has been done on how, or even if, the probability can be manipulated by an attacker. Affects: Builds of dhcpd versions prior to version 4.4.1 when using BIND versions 9.11.2 or later, or BIND versions with specific bug fixes backported to them. ISC does not have access to comprehensive version lists for all repackagings of dhcpd that are vulnerable. In particular, builds from other vendors may also be affected. Operators are advised to consult their vendor documentation.

Affected products

ISC Dhcpd: before 4.4.1 (fixed in 4.4.1)
Opensuse Leap: version 15.0 only; version 15.1 only
Red Hat Enterprise Linux: version 8.0 only
Red Hat Enterprise Linux Desktop: version 7.0 only
Red Hat Enterprise Linux Eus: version 8.1 only; version 8.2 only; version 8.4 only; version 8.6 only; version 8.8 only
Red Hat Enterprise Linux For Arm 64: version 8.0 only
Red Hat Enterprise Linux For Arm 64 Eus: version 8.1_aarch64 only; version 8.2_aarch64 only; version 8.4_aarch64 only; version 8.6_aarch64 only; version 8.8_aarch64 only
Red Hat Enterprise Linux For IBM Z Systems: version 7.0 only; version 8.0 only
Red Hat Enterprise Linux For IBM Z Systems Eus: version 8.1_s390x only; version 8.2_s390x only; version 8.4_s390x only; version 8.6_s390x only; version 8.8_s390x only
Red Hat Enterprise Linux For Power Big Endian: version 7.0 only
Red Hat Enterprise Linux For Power Little Endian: version 7.0 only; version 8.0 only
Red Hat Enterprise Linux For Power Little Endian Eus: version 8.1_ppc64le only; version 8.2_ppc64le only; version 8.4_ppc64le only; version 8.6_ppc64le only; version 8.8_ppc64le only
Red Hat Enterprise Linux For Scientific Computing: version 7.0 only
Red Hat Enterprise Linux Server: version 7.0 only
Red Hat Enterprise Linux Server Aus: version 8.2 only; version 8.4 only; version 8.6 only
Red Hat Enterprise Linux Server For Power Little Endian Update Services For SAP Solutions: version 8.1 only; version 8.2 only; version 8.4 only; version 8.6 only; version 8.8 only
Red Hat Enterprise Linux Server Tus: version 8.2 only; version 8.4 only; version 8.6 only; version 8.8 only
Red Hat Enterprise Linux Update Services For SAP Solutions: version 8.1 only; version 8.2 only; version 8.4 only; version 8.6 only; version 8.8 only
Red Hat Enterprise Linux Workstation: version 7.0 only

Published 2019-11-01. Last modified 2026-06-17.