Reachable Assertion in Unbound - CVE-2019-25036

Vulnerability identifier: #VU53032

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2019-25036

CWE-ID: CWE-617

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a reachable assertion within the synth_cname() function. A remote attacker can send specially crafted data to the server, trigger an assertion failure and perform a DoS attack.

Unbound
cflinuxfs3
unbound (Red Hat package)
unbound (Ubuntu package)
libunbound2 (Ubuntu package)
unbound-devel
unbound-debugsource
unbound-debuginfo
unbound-anchor-debuginfo
unbound-anchor
libunbound2-debuginfo
libunbound2
libunbound8 (Ubuntu package)
SUSE CaaS Platform
SUSE Manager Proxy
SUSE Manager Retail Branch Server
SUSE Manager Server
SUSE Enterprise Storage
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux Server - TUS
SUSE Linux Enterprise High Performance Computing
SUSE Linux Enterprise Server
SUSE Linux Enterprise Server for SAP
SUSE Linux Enterprise Realtime Extension
SUSE Linux Enterprise Module for Basesystem
Ubuntu
OpenShift Virtualization

Install updates from vendor's website.

Unbound - update to 1.9.5
cflinuxfs3 - update to 0.237.0
unbound (Red Hat package) - addressed in versions 1.7.3-12.el8_2, 1.7.3-15.el8
unbound (Ubuntu package) - addressed in versions 1.6.7-1ubuntu2.4, 1.9.4-2ubuntu1.2
libunbound2 (Ubuntu package) - update to 1.6.7-1ubuntu2.4
unbound-devel - addressed in versions 1.6.8-3.9.1, 1.6.8-10.6.1
unbound-debugsource - addressed in versions 1.6.8-3.9.1, 1.6.8-10.6.1
unbound-debuginfo - addressed in versions 1.6.8-3.9.1, 1.6.8-10.6.1
unbound-anchor-debuginfo - addressed in versions 1.6.8-3.9.1, 1.6.8-10.6.1
unbound-anchor - addressed in versions 1.6.8-3.9.1, 1.6.8-10.6.1
libunbound2-debuginfo - addressed in versions 1.6.8-3.9.1, 1.6.8-10.6.1
libunbound2 - addressed in versions 1.6.8-3.9.1, 1.6.8-10.6.1
libunbound8 (Ubuntu package) - update to 1.9.4-2ubuntu1.2
OpenShift Virtualization - addressed in versions 2.6.6, 4.8.0

• https://ostif.org/our-audit-of-unbound-dns-by-x41-d-sec-full-results/
• https://lists.debian.org/debian-lts-announce/2021/05/msg00007.html
• https://security.netapp.com/advisory/ntap-20210507-0007/

• Multiple vulnerabilities in Unbound DNS Server
• Cloud Foundry cflinuxfs3 update for Unboud
• Red Hat Enterprise Linux 8 update for unbound
• Red Hat Enterprise Linux 8.2 update for unbound
• Ubuntu update for unbound
• SUSE update for unbound
• SUSE update for unbound
• SUSE update for unbound
• Multiple vulnerabilities in OpenShift Virtualization 4.8
• Multiple vulnerabilities in OpenShift Virtualization 2.6