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Fencer Intel
medium 6.5

CVE-2019-6470 json

dhcpd: use-after-free error leads crash in IPv6 mode when using mismatched BIND libraries

published 7y ago modified 4mo ago also EUVD-2019-16030

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
8.8%
EPSS 8.8% chance of exploitation in 30 days, percentile 95%
public exploits
0
none known

Summary

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.

Patch / fix

  • isc dhcpd 4.4.1
  • isc-dhcp Debian 13, Debian 12 4.4.1-2

debian advisories DEBIAN-CVE-2019-6470

  • isc-dhcp Ubuntu 18.04 LTS 4.3.5-3ubuntu7.1

ubuntu advisories UBUNTU-CVE-2019-6470

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • dhcp RHEL 8 12:4.3.6-34.el8
  • dhcp-libs RHEL 8 12:4.3.6-34.el8
  • dhcp-relay RHEL 8 12:4.3.6-34.el8
  • dhcp-client RHEL 8 12:4.3.6-34.el8
  • dhcp-common RHEL 8 12:4.3.6-34.el8
  • dhcp-server RHEL 8 12:4.3.6-34.el8
  • dhcp RHEL 7 12:4.2.5-77.el7
  • dhclient RHEL 7 12:4.2.5-77.el7

red hat advisories RHSA-2019:3525RHSA-2019:2060

  • dhcp SLES 12 SP5, SLES 12 SP4, SLED 12 SP4 +4 more 4.3.3-10.19.1
  • dhcp SLE Module for Server Applications 15 SP1, SLE Module for Server Applications 15, SLE Module for Basesystem 15 SP1 +1 more 4.3.5-6.3.1

suse advisories SUSE-SU-2019:2727-2SUSE-SU-2019:2727-1SUSE-SU-2019:2657-1

  • dhcp openSUSE Tumbleweed 4.4.2.P1-2.4
  • dhcp openSUSE Leap 15.1 4.3.5-lp151.6.3.1
  • dhcp openSUSE Leap 15.0 4.3.5-lp150.5.3.1

opensuse advisories openSUSE-SU-2024:10715-1openSUSE-SU-2019:2341-1openSUSE-SU-2019:2340-1

  • dhcp Alpine 3.20, Alpine 3.19, Alpine 3.18 +7 more 4.4.1-r0

alpine advisories ALPINE-CVE-2019-6470

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • bind Azure Linux 3.0 9.16.44-2
  • bind CBL-Mariner 2.0 9.16.15-3

azure linux advisories AZL-34558AZL-6326

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-6470 updated cvss 5.9

dhcp: double-deletion of the released addresses in the dhcpv6 code leading to crash and possible DoS

  • Red Hat Enterprise Linux 6 dhcp, dhclient, dhcp-common
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux BaseOS (v. 8) dhcp 4.3.6-34.el8, dhcp-libs 4.3.6-34.el8, dhcp-relay 4.3.6-34.el8, dhcp-client 4.3.6-34.el8, dhcp-common 4.3.6-34.el8, dhcp-server 4.3.6-34.el8
    fixed: vendor fix RHSA-2019:3525
  • Red Hat Enterprise Linux Client (v. 7) dhcp 4.2.5-77.el7, dhclient 4.2.5-77.el7, dhcp-libs 4.2.5-77.el7, dhcp-common 4.2.5-77.el7 Red Hat Enterprise Linux Client Optional (v. 7) dhcp 4.2.5-77.el7 Red Hat Enterprise Linux ComputeNode (v. 7) dhcp 4.2.5-77.el7, dhclient 4.2.5-77.el7, dhcp-libs 4.2.5-77.el7, dhcp-common 4.2.5-77.el7 Red Hat Enterprise Linux ComputeNode Optional (v. 7) dhcp 4.2.5-77.el7 Red Hat Enterprise Linux Server (v. 7) dhcp 4.2.5-77.el7, dhclient 4.2.5-77.el7, dhcp-libs 4.2.5-77.el7, dhcp-common 4.2.5-77.el7 Red Hat Enterprise Linux Server Optional (v. 7) dhcp-devel 4.2.5-77.el7, dhcp-debuginfo 4.2.5-77.el7
    +2 more products
    Red Hat Enterprise Linux Workstation (v. 7) dhcp 4.2.5-77.el7, dhclient 4.2.5-77.el7, dhcp-libs 4.2.5-77.el7, dhcp-common 4.2.5-77.el7 Red Hat Enterprise Linux Workstation Optional (v. 7) dhcp-devel 4.2.5-77.el7, dhcp-debuginfo 4.2.5-77.el7
    fixed: vendor fix RHSA-2019:2060
  • Red Hat Enterprise Linux 5 dhcp Red Hat Virtualization 4 redhat-virtualization-host-image-update
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

8.81% chance of exploitation in the next 30 days, higher than 95% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugs.debian.org https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=896122 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • Multiple, non-ISC dhcpd

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.