CVE-2019-6470 dhcpd: use-after-free error leads crash in IPv6 mode when using mismatched BIND libraries

What is CVE-2019-6470?

CVE-2019-6470 is a medium-severity use after free vulnerability in Opensuse Leap, published on 1 Nov 2019. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Which versions are affected by CVE-2019-6470?

It affects 19 products.

Products include Isc Dhcpd, Opensuse Leap, Redhat Enterprise Linux, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Eus, Redhat Enterprise Linux for Arm 64 and 13 more.

How do I fix CVE-2019-6470?

Upgrade to a fixed version.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2019-6470 being exploited?

There is no known exploitation of CVE-2019-6470 in the wild and no public exploit code.

Other vulnerabilities in Opensuse Leap

• CVE-2004-1006 Code injection in n/a Critical 10.0
• CVE-2002-0702 Code injection in n/a Critical 10.0
• CVE-2003-0026 Memory corruption in n/a High 7.5
• CVE-2006-3122 Denial of service in n/a Medium 5.0
• CVE-2003-0039 Denial of service in n/a Medium 5.0

All Opensuse Leap vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2019-6470, AZL-34558, AZL-6326, DEBIAN-CVE-2019-6470, GHSA-w4w8-43xj-r4wr, RHSA-2019:2060 and 8 more.