CVE-2018-5742
bind: Crash from assertion error when debug log level is 10 and log entries meet buffer boundary
Severity
ModerateRed Hat Product Security
CVSS 3.0
Review impact separately from score.
Published · December 18, 2018
Updated · November 22, 2025
Description
While backporting a feature for a newer branch of BIND9, RedHat introduced a path leading to an assertion failure in buffer.c:420. Affects RedHat versions bind-9.9.4-65.el7 -> bind-9.9.4-72.el7. No ISC releases are affected. Other packages from other distributions who made the same error may also be affected.
Statement
This flaw appears to be exploitable only when debug logging is enabled and set to at least a level of 10. As this configuration should be rare in production instances of bind, it is unlikely that most servers will be exploitable. The debug level of the bind server can be checked via the rndc status command, which will return the current trace level as "debug level". A value of 10 or above would most likely make this flaw exploitable.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Ensure that debug logging is disabled and set to 0. This can be verified on the Bind server by the rndc status command.
CVSS / CWE
CVSS 3.0 · 5.9CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-400 · Uncontrolled Resource Consumption